Invasion for Palm

From Handlogic:

Invasion is a thrilling new action shooter/adventure game engaging you in a battle to save mankind from a deadly alien race who mean to infest the Earth. As the world's last hope, you must infiltrate the Hive, exterminate all aliens, rescue any humans left alive, and ultimately destroy the Queen. Multiple objectives and multiple ways to die make Invasion a unique experience every play.

Invasion is an original concept so controls were designed naturally around the standard 6-button Palm OS device layout, immersing the player in the game world. Packaged around the proprietary game engine are all the functions expected in a quality game including performance reporting, high score listing, game saving, difficulty and volume settings.