Stronghold

You are sent to check out an abandoned asteroid base called Stronghold. As you approach, drones are launched from the surface. It may be abandoned but apparently the automatic defense system still works.

Stronghold is a arcade shooter where you must destroy the stronghold while simultaneously shooting and/or avoiding the defenses including drones, interceptors and patrol ships that all feature different attack patterns. Drones can clone themselves, interceptors come right at you and patrol ships simply patrol a predetermined pattern. Game also features different variations for each level; in some levels drones cannot be destroyed, in others a Mega-Field starts to form at the top of the screen, reducing your maneuvering room.