Why are there so many versions of Galaxian, Donkey Kong, Pac-Man, etc? Whats the point?
In many cases, games were licensed to other companies when the parent company figured they had used them up. Or, a game was so popular that another game company just wanted to license it to try and profit off of it; Dig Dug and Pac-Man were offered by both multiple companies – Pac-Man was offered by both Namco and Midway and Dig Dug was offered by both Atari and Namco. Sometimes a different set of ROMs with a different copyright date is found, a bootleg set is found, or other such versions surface and they are easy to add to MAME, so the developers offer it. In some cases, the different versions are tweaked slightly different – the game levels are in a different order, the game is harder, faster, etc. In some cases even, the ROMs are hacked to run on hardware that they were not intended to run on.
