Mashup Atlas
Guide · examples read 11 Oct 2026

How AI game mashups work: three ways to join two games

Most mashups don't fuse two games into one program. They run both games and pass data between them, load one game's character into the other, or rebuild the mechanics from scratch.

The short answer: three routes

Which route a project uses decides what you need to own and whether it can ever run in a browser.

Three ways game mashups are built
Route What actually runs Need the original games? In the catalog
Two-game bridge Both games at the same time, plus a link that passes position, input and world data between them. Yes, both. SkyCraft , ArkWeb
Character runtime One game, with an added library that runs the other game's character rules inside it. Yes: the host game, plus your own copy of the other game's data (a ROM for ER Mario). ER Mario
Rebuilt from scratch A new game written from scratch that copies how the mechanics feel, not their code or assets. No. Blockrealm , Hollow Warden , Night Swing , Kickflip Ops , Block City , GameMash

What each route looks like

Schematic drawings, not screenshots. Boxes are programs or data; arrows show which way information flows.

Two-game bridge Game A + plugin and Game B + plugin both run; they exchange state through shared memory. Game A + plugin Shared memory Game B + plugin ⇄ ⇄
Two-game bridge. Each game gets a small add-on. The add-ons write and read the same block of memory, so one game can drive the player while the other supplies the world.
Character runtime Host game world feeds Loader + library, which drives Guest character. Host game world Loader + library Guest character → →
Character runtime. A mod loader injects a library into the host game. The library runs the guest character's physics and animation and reads the host's collision, so the character moves through the host's world.
Rebuilt from scratch Observed behaviour is re-created as New code, which runs in browser or desktop. Observed behaviour New code Browser or desktop → →
Rebuilt from scratch. Nothing from the original games runs. The creator re-creates each mechanic from how it behaves, which is why it can run in a browser without game files.

Where AI fits, and what the sources say

The trend spread online as “AI video game merging”, and toolkits now package the hard parts for AI coding agents. Universal Modder, for example, describes skills for scouting a game's internals, reverse engineering, injecting code or passing data through, and testing.

The project pages themselves say much less. Here is what each catalog entry's own source states:

  • Blockrealm

    AI use not stated

    This entry does not make a separate AI attribution claim for the named build.

  • Hollow Warden

    AI use not stated

    This entry does not make a separate AI attribution claim for the named build.

  • Night Swing

    AI use not stated

    This entry does not make a separate AI attribution claim for the named build.

  • Kickflip Ops

    AI use not stated

    This entry does not make a separate AI attribution claim for the named build.

  • Block City

    AI use not stated

    This entry does not make a separate AI attribution claim for the named build.

  • SkyCraft

    AI use not stated

    The README doesn't say whether AI tools were used to build it.

  • ER Mario

    AI use not stated

    The README doesn't say whether AI tools were used to build it.

  • ArkWeb

    AI agent setup guide

    The repo includes step-by-step instructions written for AI coding agents to check, build and install it. It doesn't say whether AI was used to make the mod.

  • GameMash

    AI use not stated

    The README doesn't say whether AI tools were used to build it.

So treat “made with AI” as a claim to check per project. It describes how some creators work, not something every mashup shares.

What no route gets around

These limits come from the catalog projects' own READMEs. None is a general rule we tested.

  • You still need the games. Both bridge projects and ER Mario run on your own copies; none of them ships game files.
  • Versions are pinned. ArkWeb works only with Spider-Man Remastered v4.0630, and SkyCraft needs Skyrim's 1.6/1.7 runtime, not 1.5.97.
  • Some must stay offline. ER Mario's loader starts Elden Ring offline with anti-cheat off.
  • Saves can be affected. SkyCraft and ArkWeb both tell you to back up your saves.
  • Any two games? Not shown. No source we read shows that any pair of games can be joined this way. Each project targets specific builds of specific games.

If you want to make one

Two starting points people use. We read their pages; we have not installed or tested either.

Universal Modder

  • Skills and tools for AI coding agents doing game modding, MIT-licensed (per its README).
  • Its README says it doesn't ship game files or decompiled code, and it isn't meant for online games with anti-cheat.
  • Expect to work with a coding agent and your own game installs; results depend on the game.

Melty

  • A Windows launcher that installs published mashups into games you own (per its homepage and FAQ).
  • Creators can publish there through coding agents.
  • We haven't checked its safety or compatibility. It is not a browser game service.

Next steps

  • Where to start

    Pick between a browser tribute and a PC mod, then run the pre-install checklist.

  • Browse the catalog

    Every project above, with requirements and the date its sources were read.