The unused sprites are already in the game, you just have to modify the status bar value in the player struct. It's somewhere around 0x700 in RAM iirc. It's all setup, you would just need to code in the conditions for those status bar faces to be used. Also, an MSU-1 patch of Doom has been out for a while. The size limitation itself is unfortunately due to hard limitations of the Super FX addressing space, which is 16MBit. Doom already uses that, and thats why it was one of the most expensive SNES carts ever produced. Size is really the major limiting factor on new features, the codebase would have to be refactored and essentially run on a custom chip, that would also have to be emulated. IIRC Randy said that there was only about 16 bytes of free space in the ROM. It's extremely difficult, and I had to disable a bunch of levels just to import TNT MAP01. None of this is impossible, but it would take alot of time and effort and optimization for space. Removing Xband is hugely beneficial to ROM space. To reclaim more space, I also disable all the start up screens except for the legal screen which is required to boot. Beyond that, level simplifications and optimizations would be necessary, and perhaps measures such as less frames of animation, or sharing and reusing music. Then, you could add a decent amount. However, with Doom SNES, you're usually talking about replacement over addition, which is why a TC may ironically be more practical over a more complete ROM. I believe Sunlitspace542 only managed to fit 3 extra levels in by disabling stuff. The size limitations are brutal. Realistically, the best option would be to disable everything but Episode 1 and distribute level packs as a ROM patch of 9 levels, and treat it like switching floppies on an old computer to deal with the abyssmal sizes floppies allow. A Doom 2 TC would probably take 3-4 ROMs split this way. Hypothetically you could add a password system or start each new game with a decent amount of equipment for that part of the game, so you're not forced to pistol start every 9 maps.