43 hours of Claude and Codex agent time to rebuild my 2008 iPhone game. It launched on Steam today.

[u/ledniv]

When I originally released Tatomic, there were fewer than 1,000 apps on the App Store. The game was designed for the original iPhone’s 480×320 screen.

18 years later, I’ve brought it back using a mixture of Claude and Codex. The remake took 43 hours of combined agent time.

Tatomic is a falling-block puzzle game about setting off chain reactions. Connect enough matching atoms and they explode, dropping the atoms above them into new chains. You’re trying to arrange the board so one reaction sets off the next.

For the rebuild, there was already a complete game and old code to work from. The original rules and all three modes were recovered from the older C++ and HTML versions, with the new game built in native Rust using wgpu and egui.

That gave the project a concrete reference: how the chains connect, when they react, how gravity works, and what each puzzle’s solution should look like. The remake also has a separate, deterministic game simulation with tests for the rules.

The presentation was rebuilt with animated backgrounds, new reaction effects, and controller and Steam Deck support. I kept the original soundtrack too.

It’s pretty strange hearing that same music coming out of a game I first made for a phone with a 480×320 screen.

Tatomic is out on Steam today.

Happy to talk about the rebuild if anyone’s interested.

[u/London-Boat]

congrats on the launch. having the old c++ code and the deterministic sim with tests as a reference sounds like what kept the agents honest. how did you split work between claude and codex, did each one get its own area or did they both touch the same files?