Deep Blue

Aliens are invading the ocean and have mutated the fish and other aquatic
beings! But an A.N.G.E.L. Fish Attack Sub is on its way to blast through four
scenes of swimming terror and stop the aliens from taking over the sea.
Fortunately, the A.N.G.E.L. is helped on its way by a number of power-ups –
for instance, Healing Power completely repairs the sub and Speed Power speeds
it up. Up to three modes of attack can be used to combat the mutant fish – the
starting Pulse Shot, the destructive Swirl Cutter, and the Bubble Beam. But
the A.N.G.E.L. is not indestructible. Four colors on the A.N.G.E.L.’s eye
indicate the amount of damage the sub has sustained, and when it’s had enough
and explodes, that’s the end of the A.N.G.E.L. and the end of the game.