Cyberbig

Cyberbig is an arcade-action game with very colorful graphics. The objective and mechanics of Cyberbig are quite simple (as much as the instructions of the game want us to believe otherwise): You are stranded with your robot on a planet full of gigantic monsters called Cyberbigs and other hostile inhabitants. The goal is to escape, running through one of the most gigantic maps in the history of 8-bit software.

To eliminate the "normal" hostile inhabitants you have to shoot them once with your laser, and when they are hit, they will shrink, at which time you'll have to crouch and shoot them again to finish them off. Cyberbigs are indestructible, so the only thing left is to run away when you come across one. In each sector you must recover discs that will help you escape. Putting them together will get you a tank and help you eliminate enemies with just a single shot as well as blast doors to escape.