The player has the ability to freely move horizontally and vertically (with a few exceptions on some platform-like levels in Space Impact Plus) but can not increase the speed of the screen's auto-scrolling feature. Powerups can be picked up while going through the levels (such as missiles, bombs, and energy beams) and the player can use them when the regular projectiles are of little effect against the enemy. As each level is played, various enemy ships confront the player, some of them following strict paths, others following the ship itself and others shooting it (with the latest games the player can encounter sub-bosses midway through the level too). After losing all lives, the player is awarded a score and depending on how many enemies killed, how many powerups picked and how many levels the player passed, that score can be placed on the Top Scores page in the game's menu.
