Dave Rzepa
Software engineer. Technical lead. Systems thinker.
I build reliable systems, help teams deliver, and make complex software easier to work on. My experience spans backend services, real-time networking, cloud infrastructure, developer tools, graphics, and engineering leadership. I’m bringing that breadth to contract projects across industries.
Global contract opportunities · San Cristóbal de las Casas, Mexico
david.rzepa@gmail.com · LinkedIn
Available immediately; 40 hours per week total shared across clients; open to any contract duration.
Working hours: 10:00–18:00, San Cristóbal de las Casas, Mexico local time (America/Mexico_City).
Spoken languages: English (native), Spanish (intermediate).
Experience
Lead Programmer — Parallel
Jun 2024 – Nov 2026
Led programming on Parallel TCG across client and backend integration, resilient networking, mobile performance, delivery infrastructure and AI development tooling; later took on more design-heavy progression and onboarding work.
Projects: Parallel TCG
- AI agent access to the Unity application. Enabled LLM agents to play and inspect a live Unity application using a Unity MCP server and driver, backed by agent test scenarios, profiling and a coverage ledger. Skills: MCP, AI agents, LLM integration, C#, Python, test automation, Unity. Transferable experience: Agent integrations, application instrumentation, and automated QA for complex interactive software.
- Automated issue-to-review engineering workflows. Developed an autonomous bug-fixing workflow, deterministic issue triage, a PR readiness dashboard, and build-provenance checks connecting Jira, GitHub, and delivery pipelines. Skills: Jira, GitHub, CI/CD, developer experience, automation, AI agents, Python. Transferable experience: Internal developer platforms, engineering automation, and traceable delivery workflows.
- Established reusable agent development practices. Created repository instructions, canonical agent skills, playbooks, and coordination around shared Unity resources. Skills: AI agents, documentation, developer experience, workflow design, resource coordination. Transferable experience: Introducing AI development tools with repeatable team practices and explicit coordination.
- Built cloud observability with infrastructure as code. Made Grafana deployment reproducible on Google Kubernetes Engine using Terraform and provided KPI dashboards for engineering visibility. Also built an analytics-breadcrumb prototype. Skills: Terraform, Grafana, GKE, Kubernetes, Google Cloud, observability, analytics. Transferable experience: Reproducible infrastructure, operational dashboards, and service visibility.
- Owned build and release automation. Built and maintained GitHub-based build pipelines, platform build matrices, caching, versioning, and release delivery through Applivery and Steam. Skills: GitHub Actions, CI/CD, build engineering, release engineering, caching, Unity. Transferable experience: Repeatable releases, build performance, and multi-platform delivery.
- Refactored authentication and backend integration. Worked on login architecture, Google Play Games and Steam authentication, token refresh, and API-client integration. Skills: authentication, token refresh, API integration, C#, backend services. Transferable experience: Identity flows, external service integration, and maintainable client/backend boundaries.
- Strengthened connection recovery and message delivery. Made Parallel TCG networking more resilient after frequent disconnects. Replaced WebSockets with direct TCP and a protocol that resends messages reliably across reconnections. Also worked on resynchronization, serialization and replay correctness, a serialization analyzer and server tests in CI. Skills: networking, serialization, distributed systems, C#, static analysis, testing, CI/CD, TCP, WebSockets, connection recovery, message delivery. Transferable experience: Debugging state consistency and building checks around difficult system invariants.
- Adapted a desktop application for mobile. Optimized an existing PC game for mobile, including texture and GPU work, blur render textures, mobile rendering, and shaders. Skills: performance optimization, profiling, mobile, GPU, rendering, Unity, HLSL. Transferable experience: Resource-constrained applications, performance investigation, and cross-platform engineering.
- Rebuilt and extended a complex client UI. Rebuilt the client UI, including collection and deckbuilder views, page architecture, card movement, draft-mode screens, and reward reveal flows. Skills: UI architecture, C#, Unity, refactoring, state management. Transferable experience: Complex application interfaces and restructuring established codebases.
- Built AI simulation and evaluation tooling. Developed a headless match harness, heuristic AI, genetic deck evolution, cloud benchmarking, and server-side solo AI decks. Skills: simulation, heuristic AI, genetic algorithms, benchmarking, C#, cloud computing. Transferable experience: Automated evaluation, search and optimization, and reproducible simulation workloads.
- Designed AI-assisted progression and player onboarding. Moved an approved AI-assisted progression and onboarding redesign into MVP implementation; release planned for early November 2026. Used AI for the heavy lifting on starter decks, Paragon unlock order based on game concepts, and missions that introduce new concepts gradually. Skills: AI-assisted design, game design, progression systems, player onboarding, LLM workflows, structured data. Transferable experience: Preparing application data for AI-assisted workflows and integrating generated output with product systems.
- Expanded development throughput after adopting agentic workflows. In September–October 2026, Dave’s monthly averages were 72.5 merged PRs versus 15.4 in January 2025–May 2026; 70 Jira tickets reaching development-complete versus 23.6; and 51 bugs reaching development-complete versus 14.6. These represent 4.7×, 3.0× and 3.5× respectively. October data runs through 28 October. Development-complete means the first transition to review or branch/QA-readiness states, not a production release. Team composition and Dave’s responsibilities changed, including a shift toward more design-heavy work, so these observations do not isolate the effect of AI. QA sent back 16.4% of tickets versus 7.0% in the baseline; the figures do not demonstrate a quality improvement or a measured production defect escape rate. Skills: AI agents, engineering analytics, delivery throughput, Jira, GitHub, automated verification. Transferable experience: Evaluating engineering workflow changes using delivery data while accounting for quality trade-offs and attribution limits.
- Hand-built the networking, delivery and reactive UI foundations. Established Parallel TCG’s networking, CI, deck-builder and reactive UI foundations through hands-on engineering, before leading the move to AI-first development. The network protocol supported robust message resending across reconnections. Skills: C#, Unity, networking, CI/CD, reactive programming, UI architecture. Transferable experience: Hands-on application architecture, delivery automation and stateful user interfaces.
- Led the move to AI-first development with automated verification. Resolved hard-to-trace bugs through AI-first bug fixing backed by improved diagnostics, 900+ automated tests and human review. Led Parallel TCG’s transition to AI-first development for new code changes, establishing reusable skills, agentic CI and automated verification. Skills: AI agents, test automation, CI/CD, technical leadership, code review. Transferable experience: Introducing AI-assisted delivery with repeatable verification and human accountability.
Principal Programmer — Offworld
Jan – Jun 2024
Unreal Engine 5.4 modernization across Starship Troopers: Extermination and Squad, including an automated World Partition and Nanite level-conversion pipeline for Starship Troopers: Extermination.
Projects: Starship Troopers: Extermination, Squad
- Delivered Unreal Engine upgrade and level-conversion tooling. Delivered an automated pipeline to convert Starship Troopers: Extermination levels to World Partition and Nanite as part of its Unreal Engine 5.4 upgrade. The tooling targeted better performance, but the resulting improvement was limited. Skills: Unreal Engine, C++, Nanite, World Partition, engine migration. Transferable experience: Upgrading complex production dependencies and adopting new platform capabilities.
- Squad engine modernization. Contributed to Unreal Engine 5.4 modernization work on Squad at Offworld. Skills: Unreal Engine, engine migration. Transferable experience: Modernizing established multiplayer applications.
Lead Programmer — PopReach
May 2021 – Aug 2023
Technical architecture, an eight-person programming team, backend integration, and live releases for PAYDAY: Crime War.
Projects: PAYDAY: Crime War
- Chose and delivered a clean rebuild of PAYDAY: Crime War. Delivered the PAYDAY: Crime War rebuild within the team’s self-set deadline after choosing a clean rebuild over migrating the inherited codebase. Dave and the team manually compared the enormous inherited Unity codebase with the new game design and found almost nothing reusable beyond the artwork. Obsolete networking permeated the code, much of which would become dead code, and understanding the legacy system alone could take months. Dave weighed the delivery risk of starting again against unfamiliar bugs, maintainability and team morale. The assessment and rebuild used traditional hands-on engineering. Skills: Unity, C#, technical architecture, legacy modernization, estimation, risk assessment, technical leadership. Transferable experience: Evaluating reuse against replacement, making architectural trade-offs under uncertainty, and delivering a rebuild against an agreed deadline.
- Programming team leadership. Interviewed, hired and mentored eight programmers for PAYDAY: Crime War. Skills: technical leadership, hiring, mentoring, architecture, estimation, code review. Transferable experience: Building engineering teams, evaluating legacy systems, and setting technical direction.
- Procedural weapon recoil. Worked on the procedural weapon recoil system for PAYDAY: Crime War. Skills: Unity, C#, gameplay programming, procedural animation. Transferable experience: Procedural control of interactive motion and gameplay feel.
- Jobified, Burst-compiled animated character hitboxes. Enabled more realistic weapon-hit tracking by keeping character hitboxes aligned with animated bones. Implemented jobified, Burst-compiled orientation updates for PAYDAY: Crime War, with jobification targeting better performance. Skills: Unity, C#, Unity Job System, Burst, character hitboxes, parallel programming, skeletal animation, hit detection. Transferable experience: Parallel processing and compiled computation for animated character hitboxes.
- Jobified stats and buffs. Worked on the jobified stat and buff system for PAYDAY: Crime War. Skills: Unity, C#, Unity Job System, gameplay systems, parallel programming. Transferable experience: Structuring gameplay state updates for job-based execution.
- Jobified mission event tracking. Worked on the jobified mission event tracking system for PAYDAY: Crime War. Skills: Unity, C#, Unity Job System, event tracking, parallel programming. Transferable experience: Job-based tracking and processing of mission events.
- Established shared application foundations. Implemented dependency injection with VContainer, async/await state machines and API wrappers, a PlayFab configuration pipeline, a UniRx UI system, and an Addressables pipeline, then trained the team in their use. Skills: C#, dependency injection, async/await, reactive programming, architecture, configuration management, Unity. Transferable experience: Modular application architecture, asynchronous systems, and enabling teams through shared foundations.
- Integrated managed backend services. Integrated PlayFab authentication, remote configuration, player data and inventory, matchmaking, and multiplayer servers. Skills: PlayFab, authentication, backend services, data storage, configuration management, API integration, C#. Transferable experience: Managed service integration, identity, remote configuration, and persistent user data.
- Built serverless functions and user-data migrations. Enabled queue-backed leaderboard rewards and shared client/server logic through Azure Functions and Azure Queue Storage. Used a common DLL for the shared logic and implemented robust user-data migrations. Skills: Azure, Azure Functions, C#, serverless, data migration, queues, distributed systems. Transferable experience: Serverless backend development, shared contracts, durable asynchronous work, and evolving stored data.
- Integrated real-time communication. Integrated Photon Fusion for real-time networking and Photon Chat for messaging. Skills: real-time systems, networking, Photon Fusion, messaging, C#. Transferable experience: Real-time client applications and communication-service integration.
- Supported live delivery and operational visibility. Deployed eight feature releases and three hotfixes. Added New Relic logging, dashboards, and alerting, and helped the analytics team with KQL queries and technical graphs. Skills: release engineering, New Relic, observability, KQL, analytics, incident investigation. Transferable experience: Operating live software, release coordination, and turning telemetry into useful engineering information.
- Built continuous deployment across clients and backend environments. Enabled branch and pull-request deployments to PlayFab environments alongside automated Google Play and TestFlight releases. Built a .NET deployment tool and Jenkins pipelines with AWS build agents, Slack integration, restartable stages and deployment guards. Skills: CI/CD, Jenkins, AWS, C#, .NET, PlayFab, TestFlight, Google Play, release engineering. Transferable experience: Repeatable releases, ephemeral review environments, and guarded deployment automation.
Senior Programmer — Bossa Studios
Jan 2018 – May 2021
Distributed simulation, data-oriented systems, graphics, physics, and AI across Worlds Adrift, I Am Fish, Surgeon Simulator 2, and Hogwash, alongside a Python web service and data-science research.
Projects: I Am Fish, Surgeon Simulator 2, Hogwash, Worlds Adrift, Bossa data-science project
- Built a data-oriented entity system. Developed a pure C# entity-component system for Worlds Adrift, usable inside and outside Unity, with bitwise entity filtering and T4-generated components and marshaling to synchronize SpatialOS and ECS data. Added batch component changes, JSON entity blueprints with multiple inheritance, throttle masks for amortizing system work, Zenject dependency injection, and unit tests around core routines. Demonstrated the feasibility of decoupling the server systems from SpatialOS; full dependency removal was not completed. Skills: C#, data-oriented design, ECS, code generation, distributed systems, SpatialOS, performance optimization. Transferable experience: High-performance data processing, generated contracts and proving approaches to decoupling core systems from frameworks.
- Solved latency and distributed simulation handovers. Implemented spline-based extrapolated ship movement for latency compensation and handover between physics servers, NTP time synchronization, and diagnostic graphing in Worlds Adrift. Skills: distributed systems, networking, time synchronization, NTP, latency, C#, simulation. Transferable experience: Time-sensitive distributed applications, state handover, and diagnosing synchronization problems.
- Extended asynchronous cloud persistence. Modified Scala server code to save and load ship-blueprint XML through AWS, making extensive use of futures and promises. Skills: Scala, AWS, asynchronous programming, XML, backend services, data storage. Transferable experience: Scala backend service development, cloud persistence and asynchronous I/O using futures and promises.
- Implemented custom GPU rendering and parallel physics. Built custom Unity HDRP effects for I Am Fish: underwater scattering and absorption with compute shaders and signed distance fields, water normals, caustics, reflections, procedural glass caustics, and a jobified buoyancy simulation. Skills: HLSL, compute shaders, GPU, rendering, physics, parallel programming, Unity, mathematics. Transferable experience: HLSL GPU computing, numerical simulation, parallel execution and graphics engineering.
- Built custom visibility and performance systems. Developed custom occlusion culling for Surgeon Simulator 2 with jobified runtime baking and compute-shader portal visibility, and optimized and debugged custom netcode. Also worked on its UI and HTTP networking. Skills: compute shaders, HLSL, parallel programming, performance optimization, networking, Unity. Transferable experience: Profiling and optimizing complex real-time software with CPU and GPU workloads.
- Tuned autonomous behavior and control systems. Originated Hogwash during a game jam and developed and tuned behavior-tree heuristics, a PID controller for path following, and ORCA dynamic avoidance. Skills: heuristic AI, behavior trees, PID controllers, control systems, simulation, mathematics, C#. Transferable experience: Autonomous agents, PID feedback control, navigation and heuristic decision systems.
- Led a server-side SDK and architecture migration. Improved server performance, modularity and reuse with C# and ECS, proving a path to SpatialOS independence; full decoupling remained unfinished due to time constraints. Led Worlds Adrift’s migration from the SpatialOS Scala SDK to the C# SDK, including a bespoke data-oriented ECS and generated synchronization systems. Skills: C#, Scala, SpatialOS, distributed systems, code generation, software architecture, migration. Transferable experience: Migrating distributed services from Scala to C# while redesigning data-oriented abstractions and generated synchronization.
- Reduced vector serialization size in a distributed simulation. Implemented a new Vector3 serialization schema for Worlds Adrift, reducing the representation from 192 bits to 96 bits per entity, with often only 64 bits changing. Skills: serialization, networking, C#, bitwise operations, performance optimization. Transferable experience: Compact data formats and precise optimization of high-frequency distributed state.
- Validated an ECS across client and server. Rewrote Worlds Adrift’s Blight feature using the ECS on both client and server, exposing and filling gaps in the framework API and demonstrating its use for a substantial production feature. Skills: C#, ECS, API design, client-server systems, refactoring. Transferable experience: Validating foundational architecture through a real feature and improving interfaces from implementation feedback.
- Delivered the final Worlds Adrift update with its community. As the last developer on the Worlds Adrift team, designed and implemented its final update in collaboration with the community, including the end-of-world events. Skills: delivery, community collaboration, product design, C#, live operations. Transferable experience: Owning delivery through a product transition and working directly with users on the final experience.
- Worked on Python web services and data science. Worked on a Python web service using Django and Celery, alongside research into natural language processing, deep learning and statistical analysis. Skills: Python, Django, Celery, NLP, deep learning, statistical analysis, machine learning. Transferable experience: Python service development, asynchronous task processing, natural language processing and statistical analysis.
Lead Programmer — Future Games of London (Ubisoft)
Oct 2014 – Jan 2018
Led a three-person programming team on Hungry Shark Evolution, refactored its legacy codebase and supported live releases. Later optimized Hungry Shark World and built prototypes in the studio’s incubation programme.
Projects: Hungry Shark Evolution, Future Games of London incubation prototypes, Hungry Shark World
- Led delivery on a long-running mobile product. Managed an internal team of three programmers on Hungry Shark Evolution, maintained an established codebase, and delivered gameplay features, optimizations, and bug fixes. Skills: technical leadership, team management, mobile, maintenance, performance optimization, delivery. Transferable experience: Leading a small engineering team and sustaining a mature software product.
- Rapid prototyping and technical validation. Delivered six distinct prototypes in twelve weeks using a rapid-prototyping framework built at Future Games of London (Ubisoft). Also developed a fuller gameplay and frontend prototype and an online multiplayer prototype using deterministic lockstep with Photon TrueSync. Skills: prototyping, framework design, Unity, C#, networking, deterministic lockstep, Photon TrueSync. Transferable experience: Rapid technical validation, reusable foundations, and deterministic network simulation.
- Integrated cloud features and live operations on a mobile product. Implemented cloud-save frontend, remote JSON configuration and Amazon Insights A/B testing, analytics, error logging with LogEntries, customer-support integrations, and GameSparks live-event client, backend logic and dashboards. Later replaced GameSparks live events with an in-house backend and built workflow tools for reviewing remote configuration changes. Skills: backend services, remote configuration, A/B testing, analytics, observability, API integration, GameSparks, mobile, tooling. Transferable experience: Service integration, operational visibility, safe remote configuration, and replacing third-party dependencies.
- Hungry Shark World performance. Optimized performance-critical systems in Hungry Shark World during June–December 2017. Skills: Unity, performance optimization, mobile. Transferable experience: Improving runtime efficiency in established mobile applications.
Unity programmer, game designer and Head of Games — UNIT9
Feb 2010 – Oct 2014
Unity engineering and product design across Decromancer, Electric Tentacle, Domino’s Pizza Hero, Nano Panda, Xtreme Xrunch Kart, W.A.R.P., 3D Photo and SWIP3. Progressed from Interactive Developer to Unity3D Dev Lead, Game Director and Head of Games, with client-facing responsibility from pitches through completion.
Projects: Decromancer, Electric Tentacle, Domino’s Pizza Hero, Nano Panda, Xtreme Xrunch Kart, W.A.R.P., 3D Photo, SWIP3
- Head of Games: strategy, proposals and hiring (2014). Performed market research and developed business strategies. Served as technical and game-design consultant and prototyper on business proposals, and interviewed applicants for multiple roles. Skills: technical leadership, market research, business strategy, prototyping, hiring, technical consulting. Transferable experience: Connecting technical feasibility, product direction, commercial proposals, and recruitment.
- Creative direction and lead engineering on Decromancer (2013). Creative Director and Lead Unity programmer: game design, UX, narrative and copywriting, art direction and marketing, alongside C# engineering using NGUI and Flurry Analytics for iOS and Android. Worked closely with an illustrator, provided creative briefs and feedback, and developed narrative and gameplay direction. Skills: Unity, C#, NGUI, Flurry Analytics, iOS, Android, UX, creative direction, product design. Transferable experience: Owning both implementation and product direction, communicating across design and engineering.
- Procedural systems and lead development on Electric Tentacle (2012). Enabled zone-specific changes to procedural level generation without code edits. As lead Unity programmer and lead game designer, built modular infinite-level generation using Perlin noise and object pooling for performance. Used C#, SpriteManager2 and Flurry Analytics for iOS and Android, and designed gameplay and UX. Conceived the shift from Nano Panda’s puzzle mechanic to an endless runner, built the initial prototype and worked with Chillingo to refine the casual-player experience. Skills: Unity, C#, procedural generation, Perlin noise, object pooling, iOS, Android, UX, performance optimization. Transferable experience: Reusable generation systems, configurable content, and allocation-conscious application engineering.
- Procedural geometry and scoring for Domino’s Pizza Hero (2011). Lead Unity programmer. Developed real-time mesh and texture deformation and mesh relaxation algorithms, analyzed dough shape to score evenness, and generated simplified mesh colliders for topping physics. Integrated native plugins and Google Analytics, and built UI view and transition systems. Skills: Unity, C#, procedural geometry, mesh deformation, physics, algorithms, native plugins, Google Analytics, UI architecture. Transferable experience: Interactive simulation, geometric algorithms, native integration, and measurable product experiences.
- Programming, gameplay and level design for Nano Panda (2011). Sole programmer and lead Unity developer on Nano Panda, implementing the project in C# with EZGUI and SpriteManager2, and contributing gameplay and level design. Skills: Unity, C#, EZGUI, SpriteManager2, gameplay design, level design. Transferable experience: Delivering an interactive product across programming and design responsibilities.
- Unity development and game design for Xtreme Xrunch Kart (2010). Unity programmer and game designer, contributing C# implementation, Unity GUI, gameplay design and level design. Skills: Unity, C#, UI, gameplay design, level design. Transferable experience: Building complete interactive experiences and collaborating across implementation and design.
- W.A.R.P. (2010). Programming, game design and sound design on W.A.R.P. at UNIT9. Skills: Unity, programming, gameplay design, sound design. Transferable experience: Combining engineering, interaction design, and audio implementation in a shipped project.
- Built reusable architecture and interface frameworks. Provided reusable UI, transition and geometry frameworks across UNIT9 projects. Built view and transition sequencing used in Domino’s Pizza Hero and Electric Tentacle, plus procedural Bézier and B-spline track generation. Produced UML diagrams, technical specifications and interfaces between Unity and layers built by other teams. Skills: software architecture, UML, technical specifications, API design, UI architecture, C#, splines, framework design. Transferable experience: Reusable C# application frameworks, Bézier and B-spline geometry, clear subsystem boundaries, technical design and animation sequencing.
- Combined analytics, UX and rapid prototyping. Selected analytics events and analyzed results across several games using Flurry and Google Analytics. Designed UX wireframes, iterated on feedback loops and balancing, and developed numerous prototypes at UNIT9. Considered retention, conversion, acquisition cost and revenue metrics in product design. Skills: analytics, Flurry Analytics, Google Analytics, UX, wireframing, prototyping, product design. Transferable experience: Turning user behavior and product requirements into testable prototypes and informed design decisions.
- Progressed from Interactive Developer to Head of Games. Interactive Developer (Feb 2010–Jun 2011), Unity3D Dev Lead (Jun 2011–Oct 2012), Game Director (Sep 2012–Jan 2014), then Head of Games (Jan–Oct 2014). Responsibilities grew from Flash and Unity development, iOS gameplay and pitch prototypes to architecture, developer coordination, game design, art direction, business and marketing strategy, and client-facing work from pitching through completion. Skills: Flash, Unity, technical leadership, game design, prototyping, client communication, product strategy. Transferable experience: Combining hands-on engineering with product direction and client delivery.
- Project involvement: 3D Photo. Worked on the UNIT9 3D Photo project during November 2010–January 2011. Skills: project collaboration. Transferable experience: Experience contributing to a photo application.
- Project involvement: SWIP3. Worked on the UNIT9 SWIP3 project, a swipe-controlled puzzle game for Android Wear. Skills: project collaboration. Transferable experience: Experience contributing to a wearable-device game.
Open-source and personal software engineering — Independent projects
Selected projects
ZzzOps agentic engineering workflow, HyperTween Unity ECS framework, and earlier simulation and tooling experiments. Also conceived and directed the AI-assisted development of this multilingual career assistant.
Projects: ZzzOps, HyperTween, Void Exiles, Ask me about Dave Rzepa — AI career assistant
- Created ZzzOps, an open-source agentic engineering workflow. ZzzOps turns project policy, specifications, tasks and dependencies into a durable goal graph backed by GitHub Issues, and provides autonomous coding agents with verification, blocker handling and resumable execution. Its Python-based implementation supports Codex and Claude Code plugins and is published under Apache-2.0. Skills: AI agents, agentic engineering, Python, GitHub API, developer tooling, workflow design, verification, open source. Transferable experience: Engineering the orchestration, durable state, feedback loops and operating boundaries around autonomous coding agents.
- Created HyperTween, a Unity ECS tweening framework. Built an MIT-licensed C# tweening framework on Unity ECS for high-performance transform updates. HyperTween provides a fluent API, extensible outputs, complex sequencing, accurate timing, conflict detection and compatibility with managed Unity components. Developed it almost entirely through traditional hands-on coding. Skills: Unity ECS, C#, data-oriented design, Burst, Unity Job System, performance optimization, API design, animation, open source. Transferable experience: Data-oriented library design, efficient parallel workloads, precise sequencing, and accessible APIs over performance-focused internals.
- Explored simulation, numerical optimization and programmable UI. Explored Unity NetCode and HDRP in Void Exiles, with dynamically sized matrix and vector classes for bounded-variable least-squares thruster allocation, a hybrid GameObject view layer, XML-based customizable UI binding, and runtime C# compilation for player control macros. Skills: C#, Unity ECS, NetCode, HDRP, least squares, numerical optimization, simulation, XML, runtime compilation. Transferable experience: Vector and matrix mathematics, bounded-variable least-squares optimization, programmable C# software, data-oriented simulation and user-configurable interfaces.
- Designed a career assistant and directed its AI-assisted delivery. Took a career-assistant product from concept to a publicly deployed service by directing an AI coding agent. Designed the product and user experience, set feature priorities, and guided implementation, review and iteration through hands-on feedback, with Codex carrying out the implementation. Skills: product design, UX, AI-assisted development, agent direction, Codex, production delivery. Transferable experience: Turning a product concept into a deployed service by directing an AI coding agent, reviewing results and iterating on the user experience.
Intern — Pixel Addicts
May – Sep 2008
Ported CPU video-effect plug-ins from Windows to Mac OS X and developed GLSL shader effects for Resolume Avenue.
Projects: Resolume Avenue video-effect plug-ins
- Ported video effects and developed GLSL shader plug-ins. During a 2008 internship at Pixel Addicts, ported a collection of CPU-based video-effect plug-ins from Windows to Mac OS X and developed GLSL shader-based video-effect plug-ins for Resolume Avenue. Skills: GLSL, shaders, cross-platform porting, Windows, Mac OS X. Transferable experience: Cross-platform software migration and GPU effects outside the games industry.
Summer intern — UNIT9
Jun – Sep 2006; Jun – Sep 2007
Two summer internships at UNIT9 in London.
Projects: UNIT9 summer internships
- UNIT9 summer placements. Completed summer internships at UNIT9 in London from June to September in 2006 and again in 2007. Skills: professional collaboration. Transferable experience: Early experience in an interactive production studio.
Projects
Parallel TCG
Company or work: Parallel
About the project: Parallel TCG is a science-fiction digital trading-card game from Parallel Studios. Players choose among five factions, build decks, and compete in strategic card battles, using units, abilities and banked cards to build combinations.
Development method: Hand-built networking, CI, deck-builder and reactive UI foundations, then led the move to AI-first development for new code changes, with automated verification and human review.
Project website
Starship Troopers: Extermination
Company or work: Offworld
About the project: Starship Troopers: Extermination is Offworld’s cooperative first-person shooter set in the Starship Troopers universe. Teams of up to sixteen players fight Arachnids, complete objectives, gather resources and build defensive bases.
Project website
PAYDAY: Crime War
Company or work: PopReach
About the project: PAYDAY: Crime War was a mobile first-person shooter developed by PopReach under licence from Starbreeze. It adapted the PAYDAY heisting setting for mobile, with cooperative heists and four-versus-four competitive matches, progression and character customization. It is a separate product from PAYDAY 2 and PAYDAY 3.
Development method: The inherited-project assessment and clean rebuild were delivered through hands-on Unity engineering.
Project website
I Am Fish
Company or work: Bossa Studios
About the project: I Am Fish is a Bossa Studios physics-based adventure about four fish separated from their home in a pet-shop tank. Players guide the fish toward the ocean using swimming, flying, rolling and biting across environmental challenges.
Project website
Surgeon Simulator 2
Company or work: Bossa Studios
About the project: Surgeon Simulator 2 is Bossa Studios’ physics-based comedy surgery game, set in the Bossa Labs Medical Facility. Players perform deliberately chaotic operations while navigating environmental puzzles and a story campaign. It originally supported cooperative multiplayer and player-created levels; multiplayer was subsequently removed.
Project website
Hogwash
Company or work: Bossa Studios
About the project: Hogwash is Bossa Studios’ family-friendly asymmetric multiplayer game, developed for Apple Arcade. Three pigs try to spread mud across a farm while a farmhand attempts to keep them under control. It originated in a studio game jam.
Project website
Worlds Adrift
Company or work: Bossa Studios
About the project: Worlds Adrift was Bossa Studios’ multiplayer sandbox MMO, featuring player-created floating islands, buildable airships, exploration and multiplayer physics. Its shared-world simulation used Improbable’s SpatialOS. The game closed in 2019.
Project website
Hungry Shark Evolution
Company or work: Future Games of London (Ubisoft)
About the project: Hungry Shark Evolution is a mobile aquatic action game from Future Games of London / Ubisoft. Players control a shark, eat sea creatures, explore the ocean and progress toward larger predators.
Project website
Decromancer
Company or work: UNIT9
About the project: Decromancer is UNIT9’s single-player tactical battle-card RPG. Players build an army of illustrated cards, arrange front-line and rear-guard formations on a five-by-four board, cast spells and explore a campaign world. Dave was Creative Director and Lead Programmer.
Project website
Electric Tentacle
Company or work: UNIT9
About the project: Electric Tentacle is UNIT9’s mobile high-score game and sequel to Nano Panda. Players create electrical bolts to pull miniature animal characters through obstacles, collect stars and rescue companions in an endless-level setting. Dave led development and game design, including procedural level generation and object pooling.
Project website
Domino’s Pizza Hero
Company or work: UNIT9
About the project: Domino’s Pizza Hero is a UNIT9 and CP+B iPad experience combining pizza-making gameplay with ordering. Players stretch dough, add sauce, cheese and toppings, practice preparation challenges and compete on scores. The app connected virtual pizza creation to a real ordering flow, providing a commercial interaction-design context for Dave’s geometry and scoring algorithms.
Project website
Nano Panda
Company or work: UNIT9
About the project: Nano Panda is UNIT9’s physics puzzle game. Players launch small pandas toward targets, using the attraction between pandas to alter their trajectories, navigate hazards and collect stars. Dave worked on programming, gameplay and level design.
Project website
Xtreme Xrunch Kart
Company or work: UNIT9
About the project: Xtreme Xrunch Kart is UNIT9’s Unity-based iPhone promotional game for baby carrots. Players steer a rocket-powered shopping cart using the accelerometer, while crunching real carrots supplies an unusual input for tricks. Dave worked on Unity development, gameplay and level design.
Project website
W.A.R.P.
Company or work: UNIT9
About the project: W.A.R.P. (Wayward Asteroid Redirection Program) is UNIT9’s physics-based mobile game about defending Earth from asteroids by manipulating their paths using gravity. It featured achievements and social score comparison through OpenFeint. Dave contributed programming, game design and sound design.
Project website
ZzzOps
Company or work: Independent projects
About the project: ZzzOps is Dave’s open-source agentic engineering workflow. It gives autonomous coding agents durable goals backed by GitHub Issues, dependency tracking, verification and resumable execution, with Codex and Claude Code integrations. The implementation is Python-based and Apache-2.0 licensed.
Project website
Public repository
HyperTween
Company or work: Independent projects
About the project: HyperTween is Dave’s MIT-licensed C# tweening framework built on Unity ECS. It offers a fluent API, extensible outputs, complex animation sequencing, accurate timing, conflict detection and support for managed Unity components. It was developed almost entirely through traditional hands-on coding.
Development method: Developed almost entirely through traditional hands-on coding.
Project website
Public repository
Bossa data-science project
Company or work: Bossa Studios
About the project: A Python web-service and data-science research project at Bossa Studios, using Django, Celery, natural language processing, deep learning and statistical analysis.
Future Games of London incubation prototypes
Company or work: Future Games of London (Ubisoft)
About the project: An internal incubation programme at Future Games of London / Ubisoft. Dave built a rapid-prototyping framework and six distinct prototypes in twelve weeks. His work also covered a more developed gameplay/frontend prototype and deterministic-lockstep multiplayer prototyping using Photon TrueSync.
Void Exiles
Company or work: Independent projects
About the project: Void Exiles is a multiplayer space-game and simulation project exploring Unity NetCode and HDRP, least-squares thruster allocation, hybrid GameObject views, XML-configurable UI and runtime C# control macros.
Ask me about Dave Rzepa — AI career assistant
Company or work: Independent projects
About the project: A conversational career profile that Dave designed and brought to production by directing an AI coding agent.
Development method: Dave designed the product and directed delivery through production deployment; Codex carried out the implementation.
Project website
Squad
Company or work: Offworld
About the project: Offworld’s tactical multiplayer shooter, built around teamwork, communication and coordinated squad play.
Project website
Hungry Shark World
Company or work: Future Games of London (Ubisoft)
About the project: An arcade shark game in which players explore ocean environments and eat progressively larger prey.
Project website
3D Photo
Company or work: UNIT9
About the project: A UNIT9 photo application that turns photographs into stylized, three-dimensional artwork.
Project website
SWIP3
Company or work: UNIT9
About the project: A Unity grid puzzle for Android Wear with swipe controls: move coloured blocks on a 5-by-5 grid to match groups of three or more.
Project website
Resolume Avenue video-effect plug-ins
Company or work: Pixel Addicts
About the project: CPU-based and GLSL shader-based video-effect plug-ins, including cross-platform Windows-to-Mac OS X porting.
UNIT9 summer internships
Company or work: UNIT9
About the project: Two summer placements at UNIT9 in London, from June to September in 2006 and again in 2007.
Recommendations
Jason Woodall
2023-09-07 · Jason reported to David directly
Dave was a great pleasure to work with on PayDay: Crimewar. He was very knowledgeable and supportive throughout the entire project. He possesses a great knowledge of many aspects of development, and can help direct work in any area. I was consistently amazed by his ability to always be on top of so many aspects of the project. It was a pleasure to work with him, and he would be an asset to any company.
Author on LinkedIn
Martin Neveklovsky
2023-08-11 · Martin reported to David directly
I had the opportunity to work under Dave for almost two years, and he was an exceptional programmer, and exhibited great leadership & management skills. His work ethic inspired the entire programming team to work harder, and he knew exactly when to give his team the freedom to tackle tasks and challenges independently, with his full trust, and when to step in and offer positive guidance and assistance, whenever it was needed or requested. This allowed many under his leadership to grow as developers and programmers, and develop their confidence as well. Dave's also displayed incredible technical skills, and tackled some of the most difficult tasks himself as well.
I would definitely work with Dave again, and any organization would find him to be an extremely valuable asset, and committed team member.
Author on LinkedIn
Ed Hicks
2023-08-08 · Ed worked with David on the same team
I worked alongside Dave throughout the entire development of PAYDAY: Crime War, and his experience, knowledge, and leadership proved invaluable on a daily basis. Dave built much of the game's core gameplay, matchmaking, and networking systems, allowing us to create a co-op shooter experience that remained faithful to the original PAYDAY experience on PC. His expertise helped us to achieve an ambitious design vision that would have typically been impossible with such a small and green team. His feedback on my designs often helped to improve the overall UX design, keep things technically simple, while making things easier to manage and tune.
While building much of the game's essential systems, Dave was still able to provide mentorship to a team of programmers of varying levels of experience. Under his guidance and leadership, our team of coders thrived and flourished and the overall gameplay experience benefitted immensely from it as a result.
Dave helped to constructively support my designs, making them better, and bringing them to life. In turn, he made me a better designer. I would work with Dave for the rest of my career if I could, and he would be an invaluable asset to any project, worth numerous programmers on most teams.
Author on LinkedIn
Rodney Lum, PMP, CSM
2023-08-07 · Rodney worked with David on the same team
Dave is an exceptional lead programmer whose productivity, efficiency, and reliability set an inspiring example for the entire team.
Dave’s ability to handle complex technical challenges was impressive and was one of the main reasons we could meet tight deadlines without compromising on quality. Dave consistently delivered a diverse set of features and solutions at an impressive pace. He has a deep understanding of intricate technical details while also grasping the bigger picture of our project.
Beyond his technical talents, Dave played a vital role as a guiding lead for the entire programming team. He readily shared his knowledge and insights, offering guidance and support to fellow programmers. His willingness to help others through technical challenges and improve their skills contributed to a collaborative team environment.
I would recommend Dave to any organization seeking a lead programmer who combines technical reliability with productivity, efficiency, and a strong mentoring approach.
Author on LinkedIn
Ryan Ross
2023-08-07 · Ryan reported to David directly
It was my privilege to work closely with Dave, an exceptional lead programmer with a broad and deep understanding of programming. Despite tight deadlines, Dave demonstrated unwavering commitment, ensuring that our work was completed with quality and efficiency. His willingness to mentor others and foster a collaborative work environment were invaluable. Dave's strong work ethic and genuine character make him an asset to any team. I'd be happy to work with him again in the future.
Author on LinkedIn
Paul McDonald
2023-08-06 · Paul reported to David directly
I worked under Dave for two years and he was a total wizard. His technical skills are unmatched and it seemed like there was nothing he couldn't code. He's an incredibly heavy lifter and, in my opinion, a single Dave can't be replaced by several senior programmers. When I worked with him, his work ethic inspired me to work harder myself. He didn't micromanage and trusted me to face challenges independently. However, he was there to give me direction whenever I was lost. He was a positive voice that let me know when I had made a mistake but turned it into an opportunity for growth rather than a bashing of my ability. I would certainly work with Dave again.
Author on LinkedIn
Alexander Lee
2023-08-05 · Alexander reported to David directly
Dave is a great manager to work with. He's fun, friendly and very straight to the point. He's willing to listen to your suggestions/opinions and will usually either accept them or challenge them if something is needed. I would definitely work with him again.
Author on LinkedIn
Maddie Osness
2023-08-04 · Maddie worked with David on the same team
I found David to be very thoughtful, engaged and clear minded as a Lead Programmer. I also found him to be a fun, creative and super friendly person and I hope to one day work with him again.
Author on LinkedIn
Tatiana Martinez
2023-08-03 · Tatiana worked with David on the same team
🚀 Proud to recommend Dave, he is an exceptional Lead Programmer with whom I had the opportunity to team up, and although it was for a short time, I could see Dave's experience, knowledge and passion for game development, which is truly inspiring 🎮🌟
Author on LinkedIn
Nick McVroom
2013-04-11 · Nick worked with David on the same team
Dave is probably one of the most brilliant game programmers/designers that I have worked with; He has a thorough understanding of what makes a game fun, how to engage with the target audience, and coding principles. He is the guy that always seems to come up with an ingenious solution to a difficult problem. He is always ready to have ideas bounced of him, and gives constructive feedback.
Author on LinkedIn
Education
MEng in Computer Science, Imperial College London — First Class Honours
Updated: 2026-10-31