The Bacterions have launched an invasion with their huge space fleet, and the high command, in its infinite wisdom, has decided to send you, and only you, to deal with the threat. Armed with the most powerful space fighter they could scrounge up, bolstered by your courage, and utterly alone, you must set out into space and single-handedly destroy the entire Bacterion fleet.

Your ship is initially very weak and can be destroyed in one hit, but can be upgraded by collecting weapon power-ups. You can uncover two types of power-ups by destroying certain specially colored enemies or by wiping out all enemies of certain groups before they escape off-screen. Orange power-up pods allow you to upgrade your ship, while blue power-up pods destroy all enemies on screen when collected.

Your upgrade bar is located along the bottom of the screen. Starting from the left edge of the bar, each time you collect an orange power-up pod you advance the cursor to the right one space. If the cursor is at the rightmost position and you collect another power-up pod, it returns to the first position on the bar. From left to right there are six blocks on the bar: speed, missile, laser, double, option and shields. You can have up to six speed power-ups and four options; the other power-ups are single upgrades only. You can choose upgrades for your ship by waiting until the cursor is over the appropriate power-up, then pressing the power-up button. ~ Kyle Knight, All Game Guide