Atari 2600 Space Invaders boasts 112 game variations in all, thanks to some very unique game options. Players can configure the game to have everything from moving shields and extra-fast enemy fire to invisible invaders and zig-zagging bullets. Two players can take turns, fight at the same time, or team up on a single cannon with some interesting ways to cooperate, such as one player in charge of going left while the other controls right, or one player moving while the other player fires.