Cavern Crusader

You are in a spaceship and are “cleaning up” a new planet we’ve found so it’s
safe to colonize it. Your mission is to destroy all the crazy aliens flying
around in the various underground caverns and when they’re clear, move on to
the next cavern. There are a few different aliens types in the new caverns,
but the color of the caverns changes every level. This game is a crude clone
of Konami’s classic 1981 arcade hit, Scramble. You control your ship with the
standard Apple II keys A, Z, arrows, spacebar.

Cavern Crusader