Invader is a vertical scrolling shoot-em-up for the Nintendo Game Boy Advance. There are 8 levels to shoot through each ending with a end-boss. The player can select from 2 different ships each with specific features.

Game modes include Arcade, Survival, Boss Attack and 2 player Cooperative via the Link cable.

Enemies leave coins that can be spend in the Shop where upgrades such as weapons, extra lives and credits are available for purchase.