The engineer you call when it has to ship.

Native mobile, Unity real-time 3D, and full-stack SaaS. Eight years, 500k+ downloads, 35k monthly users, and an enterprise app whose mobile UI/UX I redesigned and implemented natively on iOS and Android. I build with AI the way a senior engineer should: directing it, verifying it, and shipping in weeks what used to take a team a quarter.

8+ Years Shipping
500k+ Downloads Led
35k Monthly Active Users
25+ Products Shipped

Extensive interactive 2D and 3D work

Mobile is where I've shipped the most.

Mobile is my specialty. Most of the games in the portfolio below are Unity titles I built and shipped to the App Store and Google Play myself. The ones I've joined include a racing title I led past 500,000 downloads and an anatomy and pathology app I reworked (interface, auth, backend) that now serves 35,000 monthly users.

The interface is where I'm most often brought in. Most recently, for an enterprise client, I redesigned and implemented their mobile app's UI/UX natively on iOS and Android: the interaction model, the flows, the screens, the performance. Before that, a puzzle game went from fragmented to shippable by rebuilding how it felt under your thumb.

And I own what comes after launch: store releases, staged rollouts, analytics and attribution, crash triage, and the live operations that keep an app running and its ratings up.

Apps I keep live on the stores
10+Unity games shipped to the stores
500k+Downloads on a title I led
35kMonthly users on an app I reworked

About Me

I'm Rafael Zuniga, a senior engineer who ships across three surfaces: native mobile, real-time 3D, and SaaS. Same standard on all of them. The interface has to feel right, it has to be fast, the backend has to hold, and it has to keep running after launch.

Most of my 8+ years have gone into products with real users. I led a racing title past 500,000 downloads. I reworked an anatomy and pathology app (interface, auth, backend) that now serves 35,000 monthly active users. Most recently I rebuilt the UI/UX of an enterprise mobile app, natively on iOS and Android, from the ground up.

I wrote an enormous amount of code before AI existed. Most of the games on this page were built by hand, which is how there are so many of them, and it is why AI works for me the way it does. I adopted it early and seriously, and I use it the way a senior engineer should: to move fast on the parts that don't need me, so my judgement goes where it counts. I've also shipped AI-native products, not just used AI to write code. That combination is why one engineer can now deliver what a small team used to.

Tech Stack

Unity / URP C# Shader Programming HLSL / GLSL Compute Shaders Three.js WebGL Real-Time Rendering Performance Profiling Physics & Simulation Procedural Animation Mobile (iOS / Android) UI / UX Engineering Azure & PlayFab Python

What I Actually Do

Three surfaces, one standard: it ships, it's fast, and it holds up with real users.

Native Mobile & UI/UX Engineering

  • Native iOS and Android, plus Unity on mobile, with the interaction design done from the engineering side
  • Rebuilding apps that already have users: interaction model, flows, screens, and performance, without breaking what works
  • Store releases, staged rollouts, analytics and attribution, crash triage, live operations
  • SDK integration that stays maintainable: auth, payments, ads mediation, push, multiplayer

Real-Time 3D, Shaders & Performance

  • Custom shaders: cel shading, water, compute-based volumetric fog
  • Performance engineering: draw-call and triangle budgets, 60+ FPS on modest hardware
  • Multiplayer and physics that survive network sync; live data driving a real-time scene
  • Tooling for other developers: animation baking, motion matching, editor workflows

Full-Stack SaaS & Cloud

  • Multi-tenant architecture, authentication and authorisation, backend APIs
  • Retrieval and vector search, scheduled ingestion, review and approval workflows
  • Azure Functions, PlayFab, Firebase, and the deployment pipeline that keeps it running
  • Products taken from zero to production by one engineer, end to end

AI-Native Engineering

  • LLM features shipped in production, grounded in real data instead of hallucinated
  • Semantic search with tenant isolation; evaluation and review loops around model output
  • AI-assisted delivery with senior review: weeks instead of quarters, without the mess
  • Finishing what AI prototyping tools started: real auth, real backend, real performance

Shipped Products I Work On

Handling technical publishing, updates, live ops, and maintenance on Google Play & App Store

Anatomist - Anatomy Learning App

Anatomist

Comprehensive anatomy and pathology learning application featuring 3,500+ questions across 26 sections. Enhanced the existing app with improved UI/UX, performance optimizations, authentication systems, and backend integrations. Achieved 35k MAU since my contributions in 2025.

Mobile Education Unity
Off-Road Champion Racing Game

Off-Road Champion

Led development of Off-Road Champion, a feature-packed off-road racing game with 500k+ downloads. Integrated critical SDKs (analytics, ad mediation, attribution, push notifications), engineered multiplayer mode, adapted 3D vehicle physics for multiplayer synchronization, and integrated Invector's third-person controller.

Mobile Racing 3D
Polygon Mayhem Puzzle Game

Polygon Mayhem

Joined an existing puzzle app with solid mechanics but fragmented UX. Redesigned gameplay input to make selecting, rotating, and placing pieces intuitive and enjoyable. Reworked interactions, built missing UI, unified flows, and polished it into a cohesive, shippable product.

Mobile Puzzle UI/UX

My Portfolio

Projects I've built from the ground up across mobile, multiplayer, and casual gaming

Bumper Aliens

A dynamic 2D shooter mobile game featuring block-based map arenas, customizable 3-part spaceships, and strategic drone systems with five unique types. Players engage in progressively challenging missions, unlock rewards through a chest system, and enhance gameplay with intuitive touchscreen controls and incremental difficulty scaling.

Mobile Unity 2D

Space Box

A thrilling 2D shooter where players build modular spaceships, battle in real-time multiplayer arenas, and unlock powerful upgrades. Featuring dynamic gameplay, diverse game modes, and cutting-edge physics, it offers endless opportunities for strategy and customization.

Multiplayer Photon Mobile

Foka GO

An addictive arcade game featuring vibrant themes, block-stacking mechanics, and endless challenges. Quirky characters, customizable features, and dynamic stages create a playful blend of strategy and timing.

Arcade Mobile

Word Wall

A single-player word game where players place letters on a constantly shifting board, challenging their skills to form words and stay in the game as long as possible!

Puzzle Casual

Dominoes

A classic dominoes experience where players face a CPU opponent with adjustable difficulty. Featuring quick, strategic matches and a sleek, intuitive interface, it's perfect for sharpening skills or unwinding with a relaxing game.

Strategy AI

Bubble Shooter

A vibrant bubble shooter game where players aim, match, and pop bubbles to clear levels. With intuitive controls and satisfying mechanics.

Casual Puzzle

3D Runner

A 3D runner with a quadruped character racing through an infinite, curved world. Featuring procedural levels and enemies resulting in a fast-paced challenge.

3D Procedural

Wormhole Madness

A challenging space puzzle game set in a dynamic, ring-filled environment where fuel management and precise navigation are essential for success.

Physics Puzzle

Marshmallow Bounce

A lively arcade game where players launch and bounce their character across a whimsical candy themed landscape. Fun, fast-paced, and endlessly entertaining.

Arcade Casual

Fly Simulation

A 3D kitchen environment featuring a fly with movement data from a Python simulation, bridged into Unity via UDP. Demonstrates real-time data integration and procedural animation techniques.

3D Python UDP Simulation

Spell Blast

A 2.5D action game built with LibGDX featuring 3D models integrated onto 2D assets. Includes 60 uniquely designed levels, three wizards with distinct abilities, diverse spell attacks and boosts, AI-driven enemies with state machines, progressive stat system, and in-app purchases.

Mobile LibGDX 2.5D Action

Stylized horror prototype with custom cel shading

An atmospheric game prototype built in Unity (URP) to explore foundational game elements: visual style, mood, and core mechanics.

🎨 Environment & Visual Style – Designed a central environment with detailed terrain sculpting, texturing, and asset placement. Developed a custom cel shader to achieve a unique stylized aesthetic that sets the visual tone.
🎥 Dynamic Camera System – Built a flexible system that transitions between three camera modes (first-person, third-person, and fixed cinematic angles) as part of exploring different gameplay perspectives.
💧 Custom Shaders – Implemented custom water shaders for realistic pond/river effects and compute-based volumetric fog system for immersive environmental depth. Optimized render calls and triangle count to maintain 60+ FPS on modest hardware.
🎮 Motion Matching Controller – Built a custom motion matching solution with tools to bake animations into any new humanoid rig for natural character movement.

Selected Technical Work

A shorter experiment: an interactive 3D scene built with Three.js.

An interactive 3D forest scene built with Three.js featuring:
🌳 Foliage System – Dynamic tree and vegetation rendering with realistic placement and variety.
✨ Particle Systems – Ambient effects including stars, shooting stars, and fireflies for atmospheric depth.
🎮 Animated 3D Character – Fully rigged and animated character model integrated into the scene.
🎛️ Real-time Interface – Interactive controls for manipulating scene elements and parameters on the fly.

MORPG Prototype

This 6-month project showcases my expertise in full-stack game development, scalable system design, and real-time multiplayer infrastructure. Built with a top-tier tech stack integrating cloud services, efficient asset management, and real-time networking.

At its core, this project is a scalable, data-driven Online Game powered by:
🔗 Addressables – Efficient asset streaming & memory management, ensuring seamless world transitions and content scalability.
🛠 PlayFab & Azure Functions – Robust backend for authentication, player profiles, economy systems (Economy V2), and data persistence.
⚡ Photon Fusion 2 – High-performance networking for players, AI-driven enemies, synchronized combat, in-game chat, and more.
🌎 Scalable MMO Architecture – Designed for thousands of zones, items, enemies, persistent player data, live events, and ongoing content expansions.
🎮 Cross-platform Compatibility – Playable in Desktop, Mobile and WebGL with keyboard & mouse, controllers and touchscreen devices.

Every aspect of this project reflects my ability to design, build, and finalize production-ready game systems, making it the definitive showcase of my ability to blend technical depth with gameplay innovation.

Want to work with me?

Tell me what you're building and what the constraint is. I take on new builds, rescues of existing projects, and short engagements to work out why something runs badly.

Hire me directly through Upwork, where my full work history and client reviews are public.

Hire me on Upwork

Based in the United States. Available for contract work.