Super Freaks 1: Ultimate Edition

Super Freaks 1 Ultimate Edition is a 2D platformer featuring single player and up to four player drop-in/drop-out cooperative gameplay.
Go to the right, jump on enemy heads, reach the exit, all of that standard stuff. When you select a level, you can choose between any of the Super Freaks before playing, as well as a whole host of other unlockable characters. There are over 20 characters total!