GAIN GROUND (Sega Master System). This preowned Sega Master System game is in good condition and includes pictured case + cover + game cartridge. Refer images. In Gain Ground, players control one of a set of characters at a time, each with different weapons. To beat a level, players must reach the exit point with at least one character or destroy all enemies on the level before time runs out. There are forty levels in the arcade version of the game.