Stay alive - Increases bonus. Grab useful items on the screen - increases power. Shoot at enemies - increases score. You are the red spaceship on the screen. Left/right/up/down keys - Steering directions, CTRL - Shoot, SPACE BAR - Drop bomb (if any). Items appear floating around the screen throughout the game. Some power your gun, some give you extra bombs, and others give you special powers. Note that not every item you take may be a benefit to you! Medals are located in the background of every level. The more medals you get, the more bonus you get at the end of the level. There are two types of weapons; the gun and the bomb. Bombs could cancel out certain enemies' weapons.