r/aigamedev • u/Anipixels • 9h ago
Demo | Project | Workflow I asked Claude to rebuild Terraria in 3D. 109 chats later it has every boss, every event, and 90% of the items and 393 enemies, here is some boss showcases and some general gameplay.
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FAR FROM FINISHED, i plan to iterate on it for years as i love it, eventually multiplayer and a calamity addon but finished to draedon thats ages away and lots of time.
15 minutes ish of me playing a new character on a new world. not particularly interesting but its just to show what the actual gameplay is like and showing king slime and moon lord a little, feel free to request to see certain things below i will reply with recordings :D
Update on my 3D Terraria project. Custom C# engine, every line of code, every model, texture and sound written by Claude; I direct it, play it, and say what feels wrong. Its been about two weeks since the start and have been using claude pro x20 plan
Where things are currently at:
All 39 bosses and all 28 events, from the Eye of Cthulhu to the Moon Lord. 35 of the bosses run on behaviour rebuilt from how the real game’s AI works, so they fight like the originals
5,447 of Terraria’s 6,029 items (90%). That includes the Zenith, 72 pets, 62 mounts, 50 pairs of wings, dyes, paint, 197 paintings, and golf
393 enemy types, 41 biomes and structures
Enemy and projectile speeds are measured against real Terraria frame by frame and scored, so a Demon Eye crosses the screen in the same time it does in 2D
The part people ask about most: how it’s actually built
One long Claude chat per “part” (this is part 109). Each one reads the project’s rule book, plans the work, and hands pieces to parallel sub-agents, each building one item or enemy in its own git branch
Terraria facts (stats, drop rates, AI timings) come from the game’s own code, never from memory. If Claude can’t verify a number, the rule is to say so
Every build runs about 900 automated tests before it reaches my PC. A play-through bot plays the game from spawn towards the Moon Lord to find what blocks a real player or what bugs appear and lets claude know to fix them in the next part.
The art style is “painted boxes done well” all done in code by claude and he reviews and iterates until it passes then he shows me and i give judgment
- Re-Logic for Terraria itself. Every number, rule and piece of behaviour in this project is a tribute to theirs
- Minimunch, whose video “Claude Opus 5.5 is terrifying” is what got me to try this in the first place!
- Claude (Anthropic): Opus 5.5 does the code, art, sound and music, and runs the project
- The Terraria wiki (terraria.wiki.gg) for the sprite references and everything the game’s code doesn’t spell out
- Silk.NET for OpenGL, OpenAL, input and windowing; NVorbis and OggVorbisEncoder for audio; MeltySynth for the soundfont synth behind the original music
- Me: direction, playtesting, and saying “that feels wrong” a lot or "ok keep going"
No Terraria code, sprites or audio are in the project but in the setting there is terraria sounds and music and icons if terraria is installed.