Nebula

Nebula is a fixed-screen shooting game very similar to Galaxian. The player controls a rocket at the bottom of the screen and fires at a formation of different alien ships at the top of the screen. Periodically the aliens drop down the screen for an assault. Different alien types are worth different points. Shooting aliens during their attack animation is worth more points. Two of the alien types can be hit an additional time (for additional points), after making them spiral out of control on the first hit.