Cosmic Raiders is a side-scrolling shoot 'em up where the player's space ship can move both left and right and there is also a radar showing the locations of enemies. In every level four bombs are dropped along with a number of fighters to ensure the bombs reach the surface of the planet. The objective of the game is simply to clear all the enemies and get the highest score possible. For every two bombs destroyed an energy star that the player can collect will appear. By picking it up the player's ship is energized with an invincible energy shield. Once all enemies have been cleared from one level the game moves on to the next.
