I'm Marc Kletz - a developer in Linz, Austria, with a decade of programming behind me and five years building games and tools professionally. I can take a project from concept to a working, shipped product, or work with existing code bases - reworking them, hunting down bugs and adding features.
Full-cycle Unity and C# for PC, mobile and VR. Gameplay systems, player controllers, combat and boss fights, animation setups, UI and custom tooling.
Software Engineering
C#, Python, C++ and Java. Automation, data pipelines, and the integrations - REST APIs, backends, third-party SDKs and full software stack.
AI and Agent Systems
Chatbots, LLM-powered applications and agent platforms: tool integration, prompt and context engineering, retrieval over your own knowledge, and the safety layer - permissions, approvals, audit and cost control.
Web Development
Fast, clean sites and web apps, front to back. A static page like this one, or a full application with a real API behind it.
Serious Games and Gamification
Training, education and simulation built as games - for companies, schools and institutions.
Consulting and Workshops
Architecture and technical leadership for your project, plus hands-on workshops on gamification, game design, or AI safety training.
Featured
Selina - an AI agent platform I built and run
Since April 2026 I have been building and running Selina, my own agent harness - a system that gives a language model tools and lets it do work on a machine.
Selina is a personal research and development project - currently just a proof of concept. But it is the same shape of system that companies now want to run internally, and I have built every layer of it end to end. That means I can build the same kind of system for you, customized to your requirements.
Tool protocol with a permission gate.
Anything that touches the filesystem or runs a command passes a gate first: customizable rules, and blacklist.
Human-in-the-loop architecture.
Tool integration over MCP.
External servers expose their own tools to the agent at runtime, using the Model Context Protocol as the integration seam.
Memory blocks for durable sessions and structured memory.
Every message, file read and tool result is a discrete, addressable block. The agent decides what to keep, summarize or drop, so a long-running task stays inside its context budget.
Local TTS and STT.
Using local text to speech and speech to text implementations to talk with your agent.
Selina's interface - click the screenshot to open it full size.
EU AI Act
AI training and compliance
The EU AI Act is already in force, in stages. Since 2 February 2025, employers have had to show that the staff who use AI systems are trained on them - contractors included. Since 2 August 2026, AI-generated content has to be disclosed. Higher-risk systems carry documentation, testing and incident-reporting duties that step in through 2027 and 2028. For most companies the practical question is simple: who trains the team, and how is it proven?
I can help you with
Training your team on the AI tools you actually use
Build AI Act-aligned training material for your staff, your contractors and your suppliers.
Assess and verify competence through gamified tests.
Talk and run workshops on AI for your team, your event or your management.
Educate your team on what AI can actually do - its weaknesses and inherent risks.
Selected work
Reference projects
Selina
AI agent platform - 2026
A full agent harness built from scratch: tool protocol and permission gate, MCP integration, block-based memory, task queue, cost control and a streaming browser UI. Read the detail above.
Discovery Islands
Kletzgames - own IP - 2026
A cozy 3D hidden-object puzzle game built with Unity and C#. Handcrafted islands you rotate and explore, interactive puzzles, and a full progression and save system. In development for PC (Steam) and mobile. Steam page.
Rarebyte
Professional - Software Developer - 2021-2025
Four and a half years at an established Austrian games studio. Unity feature development for client work and in-house games, internal tools to speed up the team, and long-term support and client communication for a serious-games commission. Contributed to titles including Hyperspaced and Emergency Operator. A written reference is available on request. The three titles in detail.
Detecting Staves and Measures in Music Scores with Deep Learning
Master's thesis - WoRMS 2021, Alicante
My master's research, co-authored with Alexander Pacha (TU Wien) and published in the proceedings of the 3rd International Workshop on Reading Music Systems. A deep-learning approach to finding a score's structural elements - staves, measures and system measures - trained and evaluated across two public datasets. Read it on arXiv.
Neural Snake
Personal project - C# / Unity - 2021
A neural network written from scratch, no library, evolved with a genetic algorithm until it learns to play Snake: hand-designed fitness, a breeding scheme, and a feed-forward pass implemented line by line.
Personal Projects
Simulations and experiments
GPU simulation, procedural generation, and small games - some of them playable in the browser right here. See them all.
Working together
How I work
You directly talk to the person building it.
Remote work over web calls - or in person if you are based in Austria.
Transparent and sprint-based.
One or Two-week cycles with a demo or an update at every step, so you always know where the project stands.
Solo by choice, connected by design.
Where a project needs art, sound or extra hands, I bring in trusted people from the local Austrian network.
Beyond the work
Community
Founder and Chairman of Game Dev Linz.
I founded and chair the regional developer community - organizing events, coaching developers, and presenting at universities and across the local tech scene.
Conducting.
Outside of work I am studying and practicing as a conductor for two local bands and learning to compose.
Engagement
Ways to work together
Hourly
Small tasks, fixes and technical consulting, billed by the hour.
Day rate
Workshops, on-site consulting and training days.
Project
A defined scope and a fixed price, with a buffer built in for the unknowns.
Retainer
Ongoing development at a reduced rate, for the projects that keep growing.
