I asked Codex 5.4 to reverse engineer a DOS game with no source code. It’s been running for 6 hours, I can’t look away. It unpacked assets, disassembled the EXE, rebuilt the renderer, and built my childhood favorite SkyRoads in Rust! Now think of all the games we can revive.

open sourcing all my prompts so far, plan files, and current progress here so you can follow along or reverse engineer your own project:

@apples_jimmy One of my hobby for AI vibe coding projects is remaking all of my Commodore 64 and Amiga games from the late 80s and early 90s ☺️

@apples_jimmy This is the sign to do it!! 😊

Wow want some credits?

Sir absolutely 🙏 I have so many ideas :)

There are even more layers in your choice of game: 1) SkyRoads was a breakout for a 🇪🇪 group called Bluemoon, in 1993: 2) same team co-founded Kazaa, and then Skype in 2003 3) After exiting Skype, Jaan Tallinn became a prolific AI investor (incl DeepMind, Anthropic) and AI safety philantrophist and Ahti is building a very AI-driven co @StarshipRobots

Whoa, this is amazing

6 hours autonomous EXE disassembly is wild but makes sense. Reverse engineering is mostly pattern recognition, and that is what Codex is built for.

Yep! Basically has been reading, storing, and then patching till it gets tests passing

EVERY GAME WILL BE ON PC

Or finally ported to Mac!!!

Sure, More the merrier! Straight to Apple Silicon!

Lode Runner!

hahah yessss

the fact that it chose Rust for the rewrite is the quietly impressive part. it didn't just transliterate x86 assembly into C... it understood the game's structure well enough to pick a modern language and rebuild the renderer from scratch. this opens up a whole preservation angle that the retro gaming community has been doing by hand for decades. imagine pointing this at every abandonware title from the 90s

100% and it’s part of why I didn’t ask it to pick a certain language or framework, I wanted to see which path it thought would be the least friction

Oh wow. I wanna revive this one.

do it!

Next weekend. 🙂

did it actually disassemble it or simply hallucinated the game from scratch or from what it found on web

Nope! It’s been running full debugging logs and porting files, and I’ve seen it patch based off everything it’s disassembling. Genuinely been amazing to watch

wild

Unreal

bro you literally inspired the thought yesterday

I love it! This is the new “snake game” ahahah

You've inspired me. I have ChatGPT 5.4 trying to decompile Bubsy (SNES) now.

Hahah let’s gooo

@apples_jimmy Following just because it’s sky roads. Be still my childhood heart ❤️

@apples_jimmy Hahah too many memories racing close to the edge

I played this so much as a kid

same!

what do you mean you just said "build lode runner"?

I gave it the directory and I said reverse engineer this game, do not infer anything, it needs to be a true 1:1 port that runs natively And then it unpacked assets, ran tons of tests and started mapping all of it. I’ll put it all on Git and share prompts too!

I've been trying to build F-zero with each model release and it's all failed so far - might try it with GPT 5.4 lol

can someone do this for bubble bobble with online co-op?

omg this was my favorite game

I was thinking of doing one of these with an old BBS door like Legend Of The Red Dragon 2, which had simultaneous multiplayer and an overhead map view. Could be a lot of fun as a chaotic 300 player server if you got traction, and the game as released was missing quest content

that would be so sick!

Do WordStar 4.0 and Ser Reshi will die horribly in The Winds Of Winter.

hahaha

i know codex is goated. While i am a Gemini Guy. I made a short summary on Codex.

yeah I’m really impressed, it’s great

expecations are high from my side for gemini. already part of Chrome Built-in AI Early Preview Program. but the main part is the model and coding agents. what can we expect in the near future?

so cool, do you have a GitHub for it?

I’ll push it to git and reply here when it’s up!

thanks will be waiting!

revive this one

This must be a joke… 6 hours? How many tokens has it eaten?! I can’t get mine to work more than 5 minutes. What am I missing?

No joke the first session was 3 hours and 34 minutes, then I asked to steer the plan in another direction slightly. I started with plan mode and make sure it’s setup with a good exit criteria, after that it basically just kept pushing towards it.

Thanks, Ammaar! That’s a very good point! A well-defined exit criterion is like “trapping” the model inside a loop to prevent it from coming back empty-handed. I knew, for example, that Claude supports the “Ralph Wiggum” loop (quite similar in logic), but I never actually tried it. And I never thought I could do it with Codex too! Currently, I’m indeed the “bottleneck” between the model and the task. I’ll give it a go—let Codex score its own output and notify me only if it meets the threshold I’ve defined…

real question actually: how do you get around gpt stopping constantly? e.g.

Imagine not using TypeScript

Trying a Claude vs Codex head to head. Will see in several hours.

@thps2x I wonder if this would work for FMV games like Darkseed or Harvester, I’d like to create an Open FMV Game engine that can play them all upscaled and such

@thps2x That would be sick! I was hoping to jump to command and conquer next and see what was possible

I remember this game. It was fantastic. I probably have it on a floppy somewhere. :)

whoa! still having the floppy is awesome

I loved this game - this is super cool

same! :)

Super cool - I used to play this game every night.

Wow! Will be trying the same soon - looks promising!

Report back!

One good use of AI based reverse engineering could be the closed source game servers which went dark. This would revive a lot of old classics.

I this this will 100% happen

amazing

Hi Ammaar, How do I get access to this? I have a few ideas of my own and a specific game in mind... :-)

Just grab codex from OpenAI!

Thankyou. 😊

lol Nintendo cease and desists bout to go crazy 😢

lmaooo personal experimentation only

💀 lol things are gonna get wild lmao o even checked Nintendo still trying to sell megaman for money with steam deals lol 😆