Dev Builds Playable Daggerfall-Inspired Game Codexfall End-to-End with Astra

Developer Dimillian demonstrated building Codexfall, a Daggerfall-inspired procedurally generated game, end to end with the AI coding tool Astra, as a test of how well an AI agent can bring a full game world to life. The game is playable in the browser and serves as a concrete benchmark for AI agents on large-scale projects.

Confirmed

Workflow: Dimillian had Astra list all systems the game needed, turn the list into a roadmap document for tracking, then build the first vertical slice containing all core systems in ultra mode.
Content: Codexfall is a large procedural world with towns, dungeons, combat, talkable NPCs, plus magic and guild systems — a first-person dungeon crawler themed around steel, magic and ruin exploration.
End-to-end generation: the trailer, including its soundtrack, was made entirely by Astra; entering any seed on the new-game screen generates a brand-new world.
Iteration: Dimillian iterated from actually playing the game, polishing fast travel, combat feel and the first-person perspective.

Why it matters

The project shows AI agents covering not just code but system planning (roadmap docs), music, promo video, and seed-based procedural content generation — a fairly complete stress test of end-to-end agent development.

2026-09-06 ~ 2026-09-06 · 5 related posts

Full story(3 episodes)→

Episode 1: Developer builds explorable universe game with Astra(2026-09-05, 4 posts)
Episode 2: Dev Uses Astra Agent's Fast Feedback Loop to Polish AI-Generated Game(2026-09-06, 2 posts)
Episode 3: Dev Builds Playable Daggerfall-Inspired Game Codexfall End-to-End with Astra(2026-09-06, 5 posts)

Primary sources

Codexfall: dev builds Daggerfall-style procedural world with Astra — Dimillian · 2026-09-06 03:15 (UTC+08:00)
Dev uses Astra on ultra to blueprint systems and build a game's first vertical slice — Dimillian · 2026-09-06 03:15 (UTC+08:00)
Astra made its own game trailer including music, generates worlds from seeds — Dimillian · 2026-09-06 03:20 (UTC+08:00)

[source] Codexfall: dev builds Daggerfall-style procedural world with Astra — Dimillian · 2026-09-06
[source] Dev uses Astra on ultra to blueprint systems and build a game's first vertical slice — Dimillian · 2026-09-06
Dev iterates Codex-built first-person dungeon crawler Codexfall, playable in browser — Dimillian · 2026-09-06
[source] Astra made its own game trailer including music, generates worlds from seeds — Dimillian · 2026-09-06

1 near-duplicate retellings: Dimillian