Emulators in Games
This is page is about licensed games that have interesting emulators in them that were exploited to play other games not originally intended.
Nintendo 64 Games
007 GoldenEye (ZX Spectrum Emulator)
In 007 GoldenEye for N64, there is a fully-functioning ZX Spectrum 48x emulator that nobody knew about until 2012. The game also has 10 ROMs in it too, all of which were made by RARE. You can read more about it here.
Download: Patch (Replace with pre-patched version if you can)
Sega Smash Pack Volume 1 (Megadrive Emulator)
This was a compilation of Genesis games for the Dreamcast. It featured a Genesis emulator and a plain-text document on how to use it. You can read the full story about it here.
Download: Sega Smash Pack - Echelon
The Legend of Zelda Collector's Edition (NES / Nintendo 64 Emulator)
This was a compilation disc including the NES and N64 Zelda games in emulated form, albeit with occasional crashes and analog sensitivity being a tad more than what it should have been like.
NES emulation was present in Animal Crossing too, with modified FDS bios images and no iNES headers and only support for some mappers. The real interesting part is the N64 emulator. It was extracted in standalone format and a custom rom injector made for it.
Compatibility is very low, with only these games confirmed working: Super Mario 64, Mario Kart 64, Star Fox 64, Kirby 64 (partially working), Zelda: Majora's Mask, Zelda: Ocarina of Time, Zelda: OoT Master Quest, Duke Nukem 64, Mace: The Dark Ages, Wave Race, Star Soldier, Pilot Wings. Possibly other games too.
Download: Nintendo 64 Emu
Pokemon Channel (Pokemon Mini Emulator)
This is a game for GameCube that contained a emulator for playing Pokemon Mini games. Hackers removed the emulator to make a stand-alone Pokemon Mini emulator for GameCube, and because of their efforts later Pokemon Mini emulators were made by reverse engineering it.
Download: SHizZLE's Pokemon Mini Emulator
Pokemon Box: Ruby and Sapphire / Naruto Collection (GBA Emulator)
These compilations try to convince users that they stream GBA games through a Link Cable to play them on a GC screen. They require the GBA cartidges too, however in fact the full data for all the cartridges needed is in the GC disc, as well as a working GBA emulator, developed by Nintendo even for third-party games using it.
Compatibility is shit though - both the ROM files and the emulator are heavily modified. When the extracted ROMs are played on regular GBA emulators, or regular GBA ROMs are injected in the compilation (it doesn't support 32MB ROMs), games do play but suffer a variety of glitches mostly involving sound.
Twinbee Collection (SNES Emulator)
Pop'n Twinbee, originally a SNES game, was included in this compilation. It was emulated. However, the emulator itself is hacky. While the game ROM hasn't been altered, it was instead fragmented to four individual pieces. This practice was used with the "I Love Mickey Mouse" emulated Saturn re-releases of Mickey/Donald Megadrive games, with the ROMs similarly divided.
Going through the trouble of taking a regular ROM from the exact same size and replacing it in the compilation (for example Tiny Toons Adventures) reveal the emulator can handle it well with occasional graphical glitches, and controller problems.