Zanac

The System would transfer itself into an instrument of immense destruction if accessed the wrong way. Human beings took that risk and were punished: The System activated its defense mechanism and used its weapons against the human race. Years have passed, and the humans learned the techniques within The System. Now only one task was left: to shut down The System itself... Zanac A.I. is a 2D vertically scrolling shooter. You are flying the fighter AFX-6502 Zanac, a spaceship built by 256 Riot Fleet as man's last hope against total annihilation. On board are special weapons to help you blast through twelve screens of enemy creatures and destroy The System's home base. Zanac is divided into 12 "areas", which look like planets. The various locations range from deserts to jungles and oceans to industrial zones. The game has many different types of enemies. Its artificial intelligence program can intensify the action based on your skill level. The better you are, the more powerful The System is. The behavior of the randomly approaching enemies is based on factors such as the position of your ship on the screen, the place you last died, etc. The shooting speed of regular enemies and bosses varies as well. You'll have to fight the area boss at the end of each area (level). Area bosses are mainly presented with large, screen-filling bunker bases consisting of gun turrets and a "core." You also have limited time for fighting against the area boss; running out of time could lead to failure in entering the next stage, and the penalty of more and more enemies attacking.