Penetrator

Penetrator involves guiding your ship through a horizontally-scrolling arrangement of caverns, in a manner similar to Scramble. The ship must avoid crashing into the surface of the caverns (which have a jagged pattern of being higher in some parts than in others), or the mounted radar bases or seeker missiles. Fortunately you are armed with both a forward-shooting laser and downward-arcing bombs.

The game has a training mode, which is useful to help you practice the game with infinite lives, as well as a simultaneous 2-player mode. There's also an editor allowing you to design the cavern layout yourself, and save your creations to tape.