CODEX MORTIS

CODEX MORTIS turns spell combinations, undead companions and card packs into an isometric survivor game. It entered Steam Early Access on March 26, 2026 and reached its full 1.0 release on September 24.

The prompt was the easy part

A developer writing for publisher CRUNCHFEST says the first playable prototype came from a single request for a Vampire Survivors-style game. It made the idea tangible, but piling on enemies and features exposed performance and architecture problems. The team rebuilt the game twice before arriving at a TypeScript stack using PixiJS and bitECS.

That first-hand account describes a change in method: detailed system specifications, review of AI output and repeated playtesting replaced open-ended prompts. Steam's own disclosure says AI was used for the game's code, text, art, sound and music.

From demo to the September release

The released version has ten schools of dark magic, a roster of heroes, fourteen levels and online co-op for up to four players. Its March Early Access launch led to a full September release, with the store showing public player reviews. That is evidence of a real shipped product and feedback, though the review count does not tell us how many copies were sold.

Sources: Steam release and AI disclosure; Developer's production breakdown.

Gameplay still from the game’s official Steam gallery, captured in a browser by CoderHype on October 6, 2026.