2d platformer game built with Codex (zero code)
Details
- External ID
- 47034752
- Source
- HN
- Company
- —
- Product
- —
- Website domain
- —
- Launched
- Feb. 16, 2026
- Cohort
- —
- Upvotes
- 10
- Upvotes percentile
- 0.5316711590296496
- Tags
- —
- Fetched at
- Sept. 7, 2026, 9:25 p.m.
- Updated at
- Sept. 7, 2026, 9:25 p.m.
Description
Hi HN!On Sunday I spent a couple of hours building a short 2d platformer ("Prince of Persia" style). What's interesting is how I built it. I went for a zero-code approach, and built the whole thing using OpenAI Codex CLI and agent skills (with the progressive disclosure paradigm).You can play the game here: https://acatovic.github.io/gothicvania-codex-demo/You can see the full code, agent skills and a complete writeup here: https://github.com/acatovic/gothicvania-codex-demoSome takeaways:* This was one of the most enjoyable experiences ever!* Applying harness engineering with progressive disclosure is incredibly powerful - I treated my SKILL.md as simply a ToC (a "skills map") and took it from there* Implement -> Evaluate loops are key - I used Playwright and an evaluation checklist and the agent built and corrected automagically* I used PROGRESS.md as a memory/log mechanism for the agent, and a way to minimize context noise* The game dev agent was steered by the DESIGN-DOCUMENT.md, stipulating game objectives, layout and mechanics* I used progressive prompting - I built up the game piece wise - starting with basic player mechanics, then adding tiles, NPCs, interactions, sounds, menus - one prompt at a timeZero code written by me. Never even looked at the game engine (Phaser) API - just gave the skills a link to the documentation. The future is here!Credits to ansimuz (gothicvania assets) and Pascal Belisle (music).*NOTE:* The assets were *NOT* created by AI. Backgrounds and probably tiles you could generate with AI, but sprites are not quite there yet (I tried a number of different models). Something to explore fully in the future.Enjoy and let me know what you think!
Enrichment
- Theme
- indie hacker passion projects
- Vertical
- Media & entertainment
- Function
- Dev tools
- Audience
- Developer
- AI stance
- Not AI
- Project type
- Hobby / open-source project
- Normalized one-liner
- zero-code platformer game builder
- Manually corrected
- False
Could you build this?
Yes The author literally built this in a couple of hours using OpenAI Codex CLI without writing manual code.
Discussion
10 comments analyzed.
Competitors mentioned: Playwright CLI, Video models for animation, ControlNet with OpenPose
Concerns raised: Game physics difficult to validate via text-based checklists, Collision detection and movement edge cases hard to distinguish, Character animation and walking sequences remain painful, Video model rotoscoping looks suspicious, Animation consistency across loopable frames requires manual work
Feature requests: Higher resolution graphics support, Better motion capture for character walking and action sequences, Improved animation consistency tools
Competitors
Other products that read as similar to this one — 264 launches clear the similarity bar, closest 8 shown.
Attention rank: #143 of 265 (itself plus its competitors, highest first — normalized so YC and Product Hunt are compared fairly).
Launched 110 days after the earliest competitor.
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Other launches for this product
- No other launches for this product.
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