Caverns of Mars (1981)

An excellent arcade-style shooter, Caverns of Mars is a downward-scrolling game where players must pilot their craft through a series of five underground levels filled with alien ships, narrow passageways and a variety of obstacles, including blue diamonds, force field barriers and floating space mines. Fuel must be collected along the way, and at the bottom of the last level a Martian base must be destroyed. Horizontal sections provide variety, scrolling is smooth, and the fast paced, though methodical shooting action is intensely enjoyable, making this a truly addictive game.