Fire Birds

Firebirds is based on the the arcade game Phoenix. Your goal is to repel an invasion of an alien species related to birds. You command an armed spaceship which you can manoeuvre with right and left directions. In each level you have to destroy an entire set of a specific type of monster bird which increasingly has more backup forces supporting it. The final showdown is to confront a grotesque aviary mother ship with a very devilish appearance.