AI Is Merging Video Games Now (here's how)

Author: Better Stack · Watch on YouTube

Video authored by the channel shown, not by IANIA; all rights belong to the creator. Transcript and summary generated automatically; the original-language content is preserved.

Original language: English

Original video: AI Is Merging Video Games Now (here’s how) · Channel: Better Stack · 06:11 · Watch on YouTube

Topics: AI agents, Claude Code, Software engineering with AI, AI content generation, Open source and software ecosystems

Summary

The video tests Universal Modder, an open-source toolkit that uses AI coding agents to create mods for games, by building a Black Ops 3 Zombies experience inside GTA V. The agent analyzes the games, uses existing modding tools and knowledge-base notes, generates some assets, and repeatedly tests its work in-game. The result includes rounds, weapons, perks, and zombies, though some elements are approximations or use GTA V assets. The creator finds the experiment impressive, while noting its cost and the criticism that these mashups may not work well as full games.

Key points

Universal Modder is an open-source kit made by Rayhan and offered as a Claude Code plugin with skills, a command-line tool, and a knowledge base.
The test used GTA V story mode as the host and Black Ops 3 as a read-only guest.
The agent researched game files and scripts, converted Black Ops 3 sounds, and generated look-alike models when it could not extract the originals.
Because GTA V cannot load new models without modifying its archives, the mod draws assets through ReShade using GTA’s camera and depth buffer.
The agent wrote about 4,000 lines of C++ and used hot reload to test features in the running game.
The finished mod included rounds, a Mystery Box, a Ray Gun, Juggernog, zombies, and a custom Better Stack perk.
Some features used GTA V NPCs and weapons or generated assets rather than original Black Ops 3 models.
The build used about 210 million tokens, estimated at around $68 in API costs plus a few dollars for generated art.
Universal Modder’s process includes game reconnaissance, save backups, code reading, iterative in-game testing, and adding findings to the knowledge base.
The creator acknowledges that these mashups may be short-lived viral clips rather than games people will play, but sees the technology as an exciting way to make mods.

Chapters

Start	Chapter	Summary
00:00	Introducing Universal Modder	The video shows examples of AI-made game mashups and introduces the toolkit before setting up a test that puts Black Ops 3 Zombies inside GTA V.
01:00	Building the mod	The agent inspects the games, researches scripts and sounds, generates substitute models, and builds and tests the mod using hot reload.
02:34	Trying Zombies in GTA V	The creator plays the mod, demonstrating its arena, scoring, Mystery Box, weapons, perks, zombies, and custom perk effect.
04:38	How Universal Modder works	The creator discusses the build’s estimated cost and explains the tool’s workflow, generated art, and shared knowledge base.
06:11	Limitations and final thoughts	The video notes criticism that these mashups may not hold up as games, while the creator reflects on how AI could make modding more accessible.

Quotes

All three of these were made with AI coding agents — 00:00

it used that hot reload nearly 50 times while building this — 02:34

it used about 210 million tokens — 04:38

This is just a loop. — 05:09

I do think this is really cool. — 06:11

Concepts and entities

Universal Modder, Rayhan, Claude Code, Opus 5.5, GTA V, Black Ops 3, Script Hook V, ReShade, fal, Better Stack

Full transcript (original language)

00:00 This is real Minecraft running inside of GTA V with Minecraft TNT blowing up GTA cars. This is the Halo Warthog driving around in Minecraft. And this is Call of Duty Zombies but rebuilt inside of Minecraft. All three of these were made with AI coding agents and the developer behind them has open-sourced the whole kit called Universal Modder. You simply point Cloud Code at any game that you own and describe the mod that you want. It works out the engine for you, reads the code, even makes its own models, and then tests the running game. So, I decided to put this to the test by

00:30 asking it to put Black Ops 3 Zombies inside of GTA V and add a new perk. >> [music] >> So, Universal Modder is built by Rayhan and he’s actually turned this into a Cloud Code plugin now and it’s simply a set of skills, a command line tool, and a knowledge base of notes from mods other agents have already built. Now, one thing to clear up straight away is this is called Universal Modder, but it is pretty clear about its limitations when it comes to anti-cheat. So, hopefully there won’t be a surge of aimbots from this. Now, I’ll explain more about how all of this works later,

01:00 but first, let’s just jump in and try this. I picked two games from my Steam library. GTA V story mode is the host because you can run this with anti-cheat switched off and Black Ops 3 is going to be my guest, which means read only, so the agent will only ever read its files, but it will never launch it or change it. In Cloud Code, I used Opus 5.5 and my prompt simply asked for Black Ops 3 Zombies at the Vinewood sign with rounds, the Ray Gun off the wall, Juggernog, the Mystery Box, and one extra perk machine that you’ll see in a bit. With that prompt sent, my agent started with recon. It checked my GTA V version against Script Hook V, which is

01:32 the loader that GTA V script mods run through, then it backed up my saves and wrote its plan to a mod log file. Then it started three parallel sub agents, one for Black Ops 3 real zombie numbers from the decompiled game scripts and the wiki, one for our Black Ops 3 names and sound files, and one to find a finished GTA save. For the sound files, it actually opened up Black Ops 3 sound banks and worked out how they’re stored and wrote a converter so the round change, the Juggernog jingle, the kaboom, they’re all going to be real Black Ops 3 sounds pulled from my game install. When it comes to the models they used, apparently the tool that

02:02 extracts them needs Black Ops 3 running, which I’d ruled out. So, the machines in the box are actually look-alikes generated using F or F generated some concept art for them. In the future, I think I would just tell it that it’s okay to launch the game to get the real models. Once all of that was done, it then got started writing about 4,000 lines of C++. Apparently, GTA V can’t load new models without digging into its own archives, so the mod actually draws them itself through ReShade using GTA’s camera and depth buffer. At some point, Claude also realized that GTA V takes forever to load, so actually split the mod so the gameplay code could reload in

02:34 the running game in about 5 seconds, and it used that hot reload nearly 50 times while building this, checking every feature with screenshots. Finally, after testing all of these features itself, it then decided to shoot its own trailer, but I did take a look at that and it’s not so good. So, let’s just jump in and play this ourselves. So, I started out in normal story mode, but I just asked Claude to actually start the experience. Immediately, you can see we’re put into an arena where we have two perk machines. One’s a custom better stack one, you’ll see what that does in a bit. We also have a ray gun on the wall that we can buy. Then there’s also a mystery box over here, but you will notice these

03:04 are generated assets, so it has messed up sort of the Juggernog text that we have on the machine. It didn’t steal the real ones from Black Ops 3, but apparently it can do that. Same thing goes for the zombies here. It’s actually just using real GTA V NPCs, and the gun is also from GTA V. It’s also overlaying the score that we can see down there, and the score is working. We’re getting 10 points for each shot. And we can also see our round number as well. Luckily, I have just the exact amount of points for the mystery box, so we can go ahead and try this out. You can see it generated a model from F, so it doesn’t actually look like the real mystery box, and it’s also

03:35 spinning real Black Ops 3 guns, but then when you pick it up, it just converts to a GTA V gun. So, in this case, it’s just the RPG, but that is the end of round one, and we have successfully done our first GTA V zombies round. After playing a few more rounds, I now have enough points to actually buy the better stack perk over here, so we’ll go ahead and do that. And this is a perk that should actually randomly activate while we’re playing. So, we’ll see what it does in a bit. I’m actually going to go ahead and get a better weapon from the mystery box because the pistol is starting to be less effective now. Okay, there we go. An SMG should do the trick. I suppose I

04:06 should also buy Juggernog as well so we can get a bit more extra health. And why not try out the ray gun that’s on the wall cuz it actually tried to port the ray gun mechanics into GTA V. So, you can see it’s sort of a GTA V recreation of what the ray gun is. But it is using the real sound effects. I’ve now gone to round six and something funny, the police have actually turned up but they’re shooting at the zombies and not me. And it appears that I can’t shoot the police. So, the mod has added that in for me. So, hopefully I’m getting a little bit of extra help from the LSPD here. And there we go. The better stack perk is activating. It opens up the phone

04:38 browser on the better stack YouTube channel and subscribes. And that gives us a kaboom. So, you should definitely subscribe. So, yeah. In my opinion, that’s really not bad for a one-shot mod. And if you’re curious how much all of this cost, it used about 210 million tokens. But 99% of those were cash reads which are pretty cheap. So, API prices, this comes out to about $68 plus a few dollars of the foul art that it generated. I’m actually on the Claude Max plan so obviously I didn’t pay that and it barely burned through my usage. So, now let’s talk about how this skill actually knows how to mod so well. The main part of it is called mod any game.

05:09 This is just a loop. It searches the knowledge base, recon’s the game, backs up your saves, reads the real code, builds one working slice, checks it in the game, records it, and then writes a field note. Breaking down some of those steps, the recon is done with the CLI tool which fingerprints the engine, the anti-cheat, and where your saves live. The art that it generates comes from foul. So, sprites, textures, 3D models, sound, even voice if you need it. It is worth pointing out here, this was made by an ex-foul engineer. So, you can probably ask it to switch this part out for your own tools. But that’s probably why foul is the default. The next clever

05:39 part is the knowledge base. There are already 117 game notes in there plus 65 on techniques. Mostly written by Claude Code and Open Code. And my build actually started by reading the Minecraft in GTA note, which used the same GTA version, same loader, and reshade trick that I did. And by the end of it, it actually wrote its own note, which has all of the list of gotchas, as well as the cause and fix that it found. And the idea is that when you use this mod, if you want to help others out, you just ask it to open up a PR adding these notes to the knowledge base. So, that is how Universal Modder works. And you can see from my real testing that it does actually seem to create a working mod to

06:11 some extent. If you’re wondering what the industry thinks of this, Kotaku actually called this plague of vibe coded mashups and says that these mashups don’t hold up as games. And yeah, most of them are probably just 30-second viral clips that no one is going to actually play. But I do think this is really cool. When I was a kid, I had to learn Java to add stuff to Minecraft that could now be done in seconds. Although, I must say I am glad I did learn to code back then, as I wouldn’t know how today. Let me know what you think about all of this in the comments down below. While you’re there, subscribe. And as always, see you in the next one.