The Famicom version of Air Fortress has a ridiculously large amount of stuff unintentionally making it into the ROM. There is some uncompiled ASM code in there, some MS-DOS directory listings, some text strings from one of the EXEs used to build the game, and even more.
The Japanese cartridge was 128+128KB large.
Then they built the US NES version. Most of the 128K of graphics data was duplicate graphics, or unused. There was about 36KB of actual unique graphics. They shrunk the graphics down to 32KB by removing an image of a planet from one of the endings, and shipped it on a 128+32KB cartridge instead of a 128+128KB cartridge.
The Japanese cartridge was 128+128KB large.
Then they built the US NES version. Most of the 128K of graphics data was duplicate graphics, or unused. There was about 36KB of actual unique graphics. They shrunk the graphics down to 32KB by removing an image of a planet from one of the endings, and shipped it on a 128+32KB cartridge instead of a 128+128KB cartridge.
Source: https://tcrf.net/Air_Fortress