Because the game is 500MB+ (due to the CHD), nobody hosts it on simple ROM sites. The .zip file for MvC2 is only ~40MB (the program), but the CHD is ~500MB. If you only download the small zip, MAME will crash with a "missing CHD" error.

The frame rate was perfect. The sprites were crisp. Leo grabbed his arcade stick, the ball-top cold in his palm. He didn’t care that it was 3:00 AM. He didn't care about the flickering light or the quiet house. He picked Ryu, Wolverine, and Iron Man.

: While some NAOMI games require a CHD (Compressed Hunks of Data) for GD-ROM images, MvC2 is a cartridge-based NAOMI game, so it often only requires the ROM zip file rather than a CHD.

While MAME is an excellent and open-source preservation project, its NAOMI emulation can be taxing. For a more refined experience playing Marvel vs. Capcom 2 , you might consider these alternative emulators. However, note that these also require the appropriate ROM sets and BIOS files.

Once you've downloaded the Marvel Vs Capcom 2 CHD file, extract it (if necessary) and place it in the correct directory within your MAME setup. This is usually a "roms" or "chd" folder.

To successfully launch Marvel vs. Capcom 2 in MAME, you cannot just download a single file. You need a specific file structure consisting of two distinct components:

You put the CHD in the wrong folder. Fix: Create a folder named mvsc2 inside roms . Put the .chd inside that folder. Not in a sub-sub-folder. Not renamed.