Gothicvania Codex
A short 2D platformer demo built with Codex CLI and no hand-written code.
Official site acatovic.github.io, verified Nov 3, 2026. Linked from the developer's Show HN post and the repository README.
Where to play
Every platform this game is on. Links are checked against official sources; we never host or mirror games.
- Play free — official siteBrowserReleased · Short demoFree
Runs in a desktop browser. No download.
Browser (no download) · Official link verified Nov 3, 2026.
- View on GitHubGitHubReleased · Source code (MIT licence)Free
Source code repository, not a place to play.
GitHub
About Gothicvania Codex
A short 2D platformer demo in the style of Prince of Persia, made with the Phaser engine and playable free in the browser. The developer says he wrote no code himself: the game was built with OpenAI Codex CLI and agent skills, with Playwright used to test each step. The backgrounds, tiles and sprites are by ansimuz and the soundtrack by Pascal Belisle; the developer says they were not made by AI. The source code is on GitHub under the MIT licence.
How it was built
VerifiedBuilt with OpenAI Codex CLI and agent skills (a "game-dev" skill), in about ten prompts. Playwright drove an implement-then-evaluate loop, with PROGRESS.md and DESIGN-DOCUMENT.md files guiding the agent. The developer says he wrote no code himself.
- DeveloperREADME: demo created with no coding, using only Codex CLI and agent skills. — GitHub
Zero-code: the developer prompted Codex CLI with agent skills and let it implement and test the game with Playwright. Art and music are human-made third-party assets; the level was built in the Tiled map editor.
- Engine / framework
- Phaser
- Languages
- Not disclosed
- Team size
- Not disclosed
- Development time
- Not disclosed
- Development cost
- Not disclosed
- AI-written code
- Not disclosed
“2D platformer game demo created with no coding - using only Codex CLI and agent skills”Verification notes: AI tool, process and asset credits from the developer's Show HN post and README; play link from both; MIT licence on GitHub. Gameplay itself not checked (canvas game). An HN Arcade feature is mentioned in the README but not confirmed.
Development history
Shared on Hacker News as a Show HN post.
DeveloperHacker News (armcat)
Game performance
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Browser (official site)
No public metrics recorded for this listing.
Not publicly available: Concurrent players (site), Monthly revenue, Gross revenue.
GitHub
No public metrics recorded for this listing.
Not publicly available: GitHub stars.
Sales & revenue (all platforms)
Browser game — there are no downloads to count.
Reviews & rankings
Not yet reviewed by our editors.
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Not currently ranked.
No player reviews yet.
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Sources
| Source | Type | Published | Accessed |
|---|---|---|---|
| Show HN: 2d platformer game built with Codex (zero code) Hacker News (armcat) | Devlog | Feb 16, 2026 | Nov 3, 2026 |
| acatovic/gothicvania-codex-demo GitHub | Repository | Not confirmed | Nov 3, 2026 |
| Official game page (language check) acatovic | Official site | Not confirmed | Nov 3, 2026 |
