The opening storyline has the player discover an invasion of mutant space bats of doom headed toward Earth. To protect Earth, the player must fly his/her spaceship and shoot down wave after wave of various types of space bats.
This multi-level, shoot'em up game has 66 levels of advanced and colorful space-invaders-type action. The player can move upward and downward in addition to the usual left and right movement; this allows the player to dodge side-swiping doom bats. Destroyed bats drop gems which offer extra lives, weapons upgrades, and more. Bonus levels offer chances to obtain additional gems.