New Vampire Survivors-a-like Codex Mortis is perhaps one of the first games to proudly proclaim that everything from assets to code to music is “100 percent AI driven.”
Developer Grolaf, also known as Crunchfest, admits that the game, which took three months to create, is created entirely using artificial intelligence, with illustrations created in Chat GPT and animations created using “a shader written by Claude Code.”
No game engine was used—obviously pure TypeScript—with the developer explaining, “I'm using PIXI.js for rendering, bitECS for the backend entity component system, and Electron for wrapping it into a desktop app. This was all vibe coded using Claude Code (mainly Opus 4.1 and 4.5).” You can see this in action in the video below.
“IN Codex Mortis, Death is your weapon,” teases the blurb (thanks, PC gamer). “Mix five schools of dark magic, unleash a devastating synergy of spells, and gather armies of the undead in this necromantic hellscape. Endless builds, solo or co-op – embrace the forbidden and dominate. 100% development driven by artificial intelligence.”
The developer said they started with a prototype “just to see if it was even feasible” and continued from there.
“Maintaining a consistent art style was challenging, but GPT managed to remember what visual style I liked and maintain it across sessions,” he told one commenter. “I just used regular GPT rather than the image API. I also couldn't get the character animations to work properly, so I used shader-based jitter instead.
“This was the first time I created something without an engine. Steam's integration with Electron was not as smooth as with Unity or Unreal. I tried Tauri first, but it doesn't work very well with Steam at all.
“And the biggest takeaway: Compared to traditional app development, it's much less mentally taxing—it's like giving an exoskeleton to a construction worker, lol.”
Although the game has not yet been released, its Steam discussion forums are full of threads titled “Lmao that looks like ass“, “Garbage slop AI“, “Dangerous slippery slope“, And “100% AI created – do not buy or support this“.
I only found one thread that was ambivalent about his development, and which simply asks: “Why is everyone outraged by IA [sic] in game development?“
Commenters on r/aigamedev were less hostile.although a few answers have been deleted, so do what you will.
Those interested can try Free Steam demoalthough it currently has a mixed rating with one reviewer writing “The [free] The demo version is at least worth the money.”
