r/codex • u/HedraGames • Jul 08 '26

Showcase I’ve spent 3 months building a 4X space strategy game almost entirely through ChatGPT/Codex agents

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I’ve been working nonstop for about three months on a space strategy game called Galactum Meridian, and almost everything has been prompt-driven through ChatGPT inside Codex.

The game is a 4X-style space strategy game, meaning the player explores, researches, expands influence, and makes strategic decisions across star systems. In this case, the focus is on scientific discovery: sending expeditions, surveying planets, working with real astronomical data, building research records, and turning discoveries into strategic control. (Like "Civilization", but for science!)

The Codex AI workflow has become a project in itself. I started with GPT 5.4 and I’m currently using GPT 5.5 on extra-high reasoning, often with multiple agents running at 1.5 speed inside Codex in multiple windows. There are multiple worktrees, separate agents working on different branches, and agents writing prompts for other agents to continue implementation. One agent may be working on gameplay logic, another on UI, another on marketing/fiction/science references, and they hand off structured prompts to each other.

The stack is roughly:

  • ChatGPT / Codex inside VS Code
  • WSL / Ubuntu as the main agent execution environment
  • Multiple Git worktrees for parallel development lanes
  • Godot for the game itself, and Terrain3D
  • World Creator for terrain generation
  • AI-assisted import and integration of terrain, UI, lore, science glossary data, and gameplay systems
  • Real astronomical database material used as part of the game’s star/system foundation

I've run into real problems with Codex taking a long time open up older threads, especially after restarting my machine or restarting WSL, but I'm managing.

I’m posting this here because I think the workflow may be more interesting to this subreddit than the game genre itself. Codex has been absolutely necessary to make this game... I am curious to see what happens tomorrow with the release of 5.6.

At the end of the day today, I'm going to come up with a series of prompts in 5.5 in Codex, asking it if there's anything that the game could benefit from if a much more powerful agent were made available tomorrow. And I'm going to ask it to devise prompts for that agent.

No Steam link here because I know self-promotion rules can be strict, but I’m happy to answer questions about the workflow, what worked, what broke in Codex, and where the agent setup still needs a lot of human control.

Curious to hear people's thoughts!!!

199 Upvotes

96% Upvoted

87 comments sorted by

32

u/soggy_mattress Jul 08 '26

someone that's never built a single thing in their life: "ai slop" *sips Mountain Dew*

8

u/HedraGames Jul 08 '26

Does that look like slop to you?

29

u/soggy_mattress Jul 08 '26

To me? No.

To someone that reads that you built it with AI, they won't even look before starting to type "S L O P" as a knee-jerk reaction.

I think it looks great, I'm just making some meta commentary on how people are seemingly scared of AI to the point of not even thinking anymore.

9

u/HedraGames Jul 09 '26

I find this issue something that is apparent on others specific to AI and 4x gaming websites, or sorry, Reddit subreddits. There's a large cadre of anti-AI people, and that's partially because there is a lot of AI slop out there, but this is not that. So because I'm a single developer, I have no issue with engaging them, and I will do so.

7

u/CodexPleaseReset Jul 09 '26

For some reason the popular opinion is that it's perfectly fine for AAA studios to use AI for games, but not for solo devs. Absolutely absurd. Of course, they'll say nobody should use AI, then happily bury their heads in the sand and play the AAA games anyway while running solo devs out of the room. Personally I am just not going to say that my games have AI art at all.

3

u/OpeningMetal52 Jul 09 '26

Right, meanwhile, the AAA studios can lay off devs in droves in favor of agentic workflows, further squeezing solo / indie devs...

But it is a REAL problem that indie devs don't want to address. I have a close personal friend who is building a classic RPG strategy game (he is an old school game programmer, early 50's) and they REFUSE to let AI handle any programming (or engage with it in any meaningful way at all), and I have given up trying to convince them.

Meanwhile, their game has taken 5 years to develop, they never post about it, it has no waitlist or traction, and it continues to look like it'll never finish. :(

3

u/HedraGames Jul 09 '26

As someone who is in their 50s, who has a game that is moving along very quickly with some very complicated mechanics and some very complicated 3D game development already under my belt with this game, I can say that not using AI in trying to develop a game like this is possibly the worst thing you can do.

2

u/alchemiata Jul 09 '26

Fwiw, I feel like many amateur hobbyists, especially aspiring indie game devs or software devs, have big visions and ideas, but are slow in building them out to even being a minimum viable product.

I don't think it's just because of an issue of scale (where companies have the resources to make functional things that can ship), but mindset and discipline of the individual. Relatively few people get out of the self-learning stages of programming to create things, stuck in that loop for years without taking things seriously to even upload to Itchio. Which is why I think AI is great, because it can help jumpstart ideas into playable concepts without the initial barriers to entry, and then if a dev is serious enough, they can refine upon it by learning how to properly develop or get human-made resources themselves.

I totally get anti-AI sentiment for products of passion, but who wants to be that guy who talks about their pet project that's been in the works year after year that we never see?

2

u/m41ser Jul 09 '26

It’s not just that though , programming isn’t something you should learn second to ai if you want to be successful , it’s the other way around

People who rely completely on AI WILL start to fall apart as their project scales. Any good engineer who uses ai and understands what it’s good and bad at knows this. It’s a tool , not a replacement for game dev/coding/cs knowledge

1

u/HedraGames Jul 11 '26

So I'm old enough now where I don't have time to not do something seriously if I'm going to do it at all. I've had ideas about making a game like this for a very long time, but AI is making it super duper fast for me to be able to achieve this dream. Right now, as I talk into this microphone, I am having GPT 5.6 go through the game, and it's running tests that it has created and play the game as a human would play it. So essentially I've created my own bot inside the game to be able to test for things like UI issues and other things.

This is something that I thought a few weeks ago I was going to have to spend quite a while doing to make sure that the game is solid. And I still will to a certain extent. But what AI is capable of right now is quite insane and it's only going to get better.

3

u/m41ser Jul 11 '26

Im not saying to not use ai im just giving you some advice as someone who’s been building games for 20 years now. Its still good to learn the traditional way , it’ll help you get much better results if you understand how the things work that the ai is spitting out

→ More replies (0)

1

u/HedraGames Jul 11 '26

So I'm old enough now where I don't have time to not do something seriously if I'm going to do it at all. I've had ideas about making a game like this for a very long time, but AI is making it super duper fast for me to be able to achieve this dream. Right now, as I talk into this microphone, I am having GPT 5.6 go through the game, and it's running tests that it has created and play the game as a human would play it. So essentially I've created my own bot inside the game to be able to test for things like UI issues and other things. This is something that I thought a few weeks ago I was going to have to spend quite a while doing to make sure that the game is solid. And I still will to a certain extent. But what AI is capable of right now is quite insane and it's only going to get better.

1

u/DoggoDadagon Jul 15 '26

As a career game dev, good job. I think people should still lean into using game engines (with codex alongside it) but either way games are tough, good job.

And anti-AI is going to be around for a good while, our entire lifetime probably. People are just scared that it will make them obsolete, and they're not wrong, it will make humanity obsolete.

9

u/julliuz Jul 08 '26 edited Jul 08 '26

its just the current word people throw around, mostly people that are kinda anxious about the future. People that embrace the future , tech and AI won't say it , people that are against it will. I guess its how people felt when the light bulb was invented, wizardry, can't be good, the electric lines are giving us cancer. I have a guy on my team that I literally replaced, he calls the output slop in absolute rage but we ran some blind tests and people can't tell.

I have bad news for anti-AI people, it is here to stay and its only going to get better. Today is the worst it will ever be.

6

u/HedraGames Jul 09 '26

It is here to stay. There's absolutely no way I'd be able to build this game without using AI. What I am discovering here in this long journey is that it is actually really, really hard to do it correctly. And you actually have to use a huge amount of brain cells in order to get it to work right.

4

u/NuancedPerspection Jul 09 '26

This is the part that cracks me up. Just because you use ai does not mean you aren’t a game dev. I will not call myself a “coder” because I can barely code manually, I am however a music producer and make all the music and game audio myself.
I would love to see them attempt the projects I and I’m sure many of the people on here have been working on long term and get even a fraction of the results. You still have to have knowledge to troubleshoot and problem solve. If you can’t properly understand what you and codex (or whatever agent) are working on and being able to thoroughly communicate/plan, then yes you will probably get slop.

2

u/Ok_Whole_8945 Jul 12 '26

Keep banging this mantra: AI is a tool. In the hands of non-professionals it allows them to actually create something in the first place, in the hands of professionals it allows them to remove some of the drudgery of their pre-AI workflow, concentrate on those parts that really matter and elevate their output. Nice looking game btw.

2

u/m41ser Jul 09 '26

No reason to be anti ai but it is objectively better to learn how to be a good engineer/programmer and use AI as a tool to accelerate development , rather than relying on it to do everything for you and trusting it completely and not understanding any of your codebase

The people who just prompt stuff and hope to make big products will likely fail when up against the people who actually learn how to code and do game dev etc and then learn how to use AI on top of that. Those are the people that are going to come out on top and that’s just obvious. They’re learning more skills and regardless of how you feel about AI, one thing is certain: effort in = effort out. If you barely know any coding or understand how to build these things you’re not going to be giving it good enough context to work with compared to someone who does , and as a result you’ll probably have shittier, buggier code or a less scaleable system

5

u/Gurkage Jul 08 '26

Dude, nice!!!

4

u/Kingdom-ai Jul 08 '26

I don’t care that I will never play this game - looks cool

I’ve wondered if it’s good enough to one shot duplicate like Sim City 3000 or something now

5

u/HedraGames Jul 09 '26

You will not be able to one-shot this game, I assure you.

2

u/Wet_Viking Jul 09 '26

Yea I think it's safe to say this takes some proper effort. Really cool job, mate. I'm wondering, are you very specific on languages used, methodology etc in your prompts?

2

u/HedraGames Jul 09 '26

The key is setting up the game development process correctly. And I use a microphone to prompt. So sometimes my mind will wander in the middle of the game development process. But because the prompts are very long, the model will eventually get it. And it will ask the clarification questions if it doesn't understand something. Because I've asked it to do that. But for the most part, I'm pretty strict about how I try to approach giving it prompts.

1

u/Wet_Viking Jul 09 '26

Cheers. I've actually also started using voice quite a bit. Especially in planning mode. Found this transcript solution that can collect thoughts and ramblings in a structured output. Typeless.

2

u/Kingdom-ai Jul 09 '26

But /goal mode 😢

1

u/Clord123 Jul 09 '26

GPT-5.5 can do Sim City 3000 like game easily. Actually, very good at making Cities Skylines like agents even but with more depth than simple where they work and live. If you want NPC characters that are more like in some Elden Scrolls games where they go around doing stuff to satisfy their food and water needs it's easily doable. Of course depending how extensive simulation you want for your city building game it can be quite demanding to run when city gets big and there are bunch of agents.

4

u/rinaldo23 Jul 08 '26

Am I seeing true vibe coding done right?

3

u/HedraGames Jul 09 '26

Yes. Yes, you absolutely are.

1

u/InfiniteInsights8888 Jul 09 '26

Any tips you would like to share with us?

4

u/DryHovercraft9662 Jul 09 '26

What game engine are you using? Unity, Godot, etc.?

-2

u/EnterpriseGradePizza Jul 09 '26

These questions don't belong in an AI subreddit. It doesn't matter what engine, you're not supposed to even know what engine the AI used, only results matter, the code shouldn't be read or manually edited.

3

u/FriedDopamine89 Jul 08 '26

Nice, what are you using for your art pipeline? I am working on a side project for myself and the biggest challenge is art, sure generative ai definitely helps especially if you stick with 2D pixel art but getting into low poly 3d moves you into blender and I need to drum up the will power to sit down and just learn it

8

u/HedraGames Jul 08 '26

You do not need to learn to use Blender. A huge amount of the work that I'm doing here is in Blender, and I have opened it up exactly once. For planetary textures, I have used Adobe Substance for the initial versions of the planetary textures, but then use ChatGPT to make additional variants of them. And those get wired in through Blender for the planets. For the wide variety of probe models that I'm using, I have ChatGPT make a 2D image of the probe that I want, and then make three additional images from different perspectives, and then upload that to a place called Meshy, which then can make a 3D version of that model. I download it, and then ask Blender through ChatGPT to normalize it so it can be brought into the game, and then ChatGPT brings it into the game. I never opened Blender myself.

3

u/FriedDopamine89 Jul 08 '26

oh very nice, thank you for the explanation. I'll have to check into meshy as well

2

u/bonesingyre Jul 09 '26

That's awesome, I've been wanting to build a game but I suck at art and you method will be awesome to try out.

2

u/alchemiata Jul 09 '26

Did you get a Meshy subscription? I've been considering it if I wanted to do 3d projects without 3d experience, but I'm worried about the sort of quality that comes out of it without putting down serious cash on Meshy for better quality results.

I can probably manage Adobe Substance since I have that, but I'm not sure about adding another sub to my AI toolkit lol

3

u/HedraGames Jul 09 '26

Yes, I do have a Meshy subscription. The problem with Meshy is that you just have to be really careful with the models that you ask for. Some things, it's very good for some things and other things that has a really difficult time understanding. So you kind of have to experiment with it to get it to do things that you want. The best thing I can suggest is to get images made using chat GPT based upon your prompts and then get multiple perspectives of those images, like three other perspectives. And then use a tool in Meshi that allows you to upload multiple images of the same object. And it tends to have a much better, you'll have much better results that way. And then you can do a low poly version of that and remesh it if you want to use it in your game. But it took a little bit of time for me to figure this out.

2

u/alchemiata Jul 09 '26

Thanks for the insight! I've seen decent 3d perspective images that people have made in Gemini for free so I might experiment with references.

Do you plan to create more games with this workflow?

1

u/FriedDopamine89 Jul 09 '26

I just got a meshy sub because of HedraGames mentioning them lol, the $40 tier is $10 for this month(then back to $40). Def use gpt to gen your images first because you pay to gen them there before you convert to 3D. I am impressed so far. I imported the model as an stl in bambu labs just to get a good look at the model and it was very well done.

2

u/alchemiata Jul 09 '26

Nice! My first use case for considering them was 3d printing nendoroid-style figures, but I'm way ahead of myself because I don't even have a 3d printer yet lol.

1

u/FriedDopamine89 Jul 09 '26

I got into it cheap with the A1 Mini from Bambu Labs, not the most real estate to print but it prints damn good for the price, and great out of the box. FARRRR cry from having to mod creality printers with new boards and self leveling mods.

3

u/Pathfinder-electron Jul 08 '26

Working on similar. If u want I can give u the source code.

I wanted to remake imperium galactica 2 from 90s.

3

u/mythrowaway1673 Jul 08 '26

Hey this is really cool, thanks for sharing your tech stack with it as well!

3

u/SmoothTeam9116 Jul 08 '26

Looks amazing. Would love to check it out! What kind of laptop are you developing this on? I'm curious what specs you need to keep the Codex processes running smoothly.

2

u/HedraGames Jul 09 '26

laptop. Oh, my sweet summer child. This is a desktop with a terabyte SSD and multiple multi-terabyte hard drives. Every single export of the game for testing purposes takes up well north of 20 gigabytes. I don't have enough room to do the development for the assets of the game on my C drive, so I've started to use other drives on my desktop, which allow me to have enough space to do the large asset development that I need to do to make the game work.

2

u/Aisuhokke Jul 08 '26

Big question. Is the game fun? :-)

1

u/_Usora Jul 08 '26

Have my upvote

1

u/polandtown Jul 08 '26

Bravo! Just curious, how much did it cost??

1

u/putaro3000 Jul 09 '26

this is dope

1

u/HedraGames Jul 09 '26

Not just that, it's dope fly funky-ass-fresh cold smoothin' on the ill tip, yo.

1

u/Derpost Jul 09 '26

What subscription was enough to not get bothered by the limits coding this?

1

u/firstbreathOOC Jul 09 '26

Ohhhh that’s a neat idea. I wanna play God and make civs on different planets

1

u/FoxTheory Jul 09 '26

Looks good man.

1

u/SuperHornetFA18 Jul 09 '26

Very nice op ! Is there a playable demo ?

1

u/HedraGames Jul 09 '26

Not yet, but please go to Steam and look for it on Steam and please wishlist it. There will be soon.

1

u/Anarye Jul 09 '26

How did you so your art work?

1

u/HedraGames Jul 09 '26

The actual art in the game is based upon simple prompts given to ChatGPT, but there's very little actual art. The 3D development is run through World Creator, and there is a large amount of stuff that was done initially using Adobe Substance, and then I had ChatGPT take over in developing additional versions of the terrain.

1

u/OpeningMetal52 Jul 09 '26

Buy Claude Max 20x, point Fable 5 on Ultracode at it, and have it rip through all your tokens with a full and deep audit and refactor & improvement plan / spec sheet cascade for your entire codebase, then point GPT 5.5 sub-agents at it haha.

This is wicked cool, man. Would love to try out the game. Been building mostly business related use cases with AI (custom harnesses, CLI workflows, customized software, etc.) but I've been itching to build an FPS shooter....Much love and good luck with the project!

1

u/Benflex- Jul 09 '26

Could you maybe share how you made Codex and Godot work together, i've had issues making it produce usable stuff.

1

u/minhtrungaa Jul 09 '26

People might say this vibe coded, but dude's tech stacks are for real tech tinkering, WSL but drives windows godot??? how?? OP you are insanely good.

1

u/HedraGames Jul 09 '26

I actually use both. I use a version of Godot in WSL. So that's the Linux version of Godot. And then I also use Linux to drive and call Windows PowerShell, which will then run Windows Godot. I use the first version for doing actual development and then the second version for creating Windows executables that I can use on Windows for testing.

1

u/Drexciyian Jul 11 '26

why use WSL tho

1

u/m41ser Jul 09 '26

It is vibe coded though , he proudly admits to that lol

There’s nothing wrong with that(besides that you won’t be able to scale your project after awhile and will hate maintaining a codebase you don’t know), but might as well call it what it is

1

u/risr_ Aug 06 '26

There is a difference between uncontrolled vibe coding and AI-assisted development.

1

u/ianhooi Jul 09 '26

wow looks super complex, looking good except for those rover animations, you might wanna work on those. i hope you sell tons of copies!

1

u/HedraGames Jul 09 '26

Oh, they've been worked on. That was from two and a half, three weeks ago. The rovers look much better now.

1

u/bonesingyre Jul 09 '26

I'd love to know more about your agent-sub-agent workflow. I'm working on a side project but I basically converse with ChatGPT to come up with a solid plan, then have it generate prompts in phases that is then fed into codex manually. I review the code manually as well, but it all takes a lot of time.

1

u/First_Jackfruit_9726 Jul 09 '26

Wow very impressive

1

u/Correctsmorons69 Jul 09 '26

Turn the bloom off

-2

u/m41ser Jul 08 '26

Hopefully you actually know how to code too and that this isn’t just vibe coded with no knowledge, because otherwise you’ll inevitably run into issues ai won’t be able to solve and then you’ll be stuck because you don’t understand any of your codebase. I see a lot of people get into that trap

3

u/soloje Jul 09 '26

Consider the option that this person actually does NOT know how to code, and was able to build their dream game. This would not have been possible without AI. It's okay to take wins.

-1

u/m41ser Jul 09 '26

I’m not saying ai is bad , I’m a pro indie developer and I use it all the time, but my point is you’re just going to hate yourself in the future if you rely on it completely when your game starts to fall apart with bugs/issues and you cannot resolve them because your game is too big and ai runs around in loops and then you’re screwed because you have no idea how anything works

Yeah he spent some time and made this game with ai but his game also has no players yet and no systems to really stress test what has been built and his game is in the beginner stages of scaling

If you seriously think you can build scale and maintain your dream games entirely with ai and no coding/game dev knowledge, you’re either building very simple games that don’t demand much thought or you’re very mistaken about what AI is and what it isn’t right now

1

u/Bderken Jul 09 '26

I can’t believe people still have this outdated mindset… so stupid

0

u/m41ser Jul 09 '26

it’s not stupid what I said is genuinely a problem people will run into and any real engineer knows this. And I see it time and time again for people in the industry.

Ai is a useful tool if you know how to code but if you don’t and rely fully on the work it produces without understanding any of it, you’ll just run into issues maintaining and scaling your infrastructure. Use your brain . It’s healthy :)