In Search of Dr. Riptide

You are Nick Nautilus, Secret Naval AgenT (S.N.A.T.) 1138. S.N.A.T. 1138 Mission Summary: You have been called into action to seek and destroy the undersea laboratory of Dr. Tiberius Riptide, a mad scientific outcast. You have been ordered to use any means necessary to put Dr. Riptide and his secret lab out of commission...for good. A JASON submersible will be issued to aid your search. The JASON's small, manageable size will make it an invaluable asset. Mission Background: Riptide was banished from the scientific community after he announced plans to construct devices of heinous mass destruction to the population of the world's oceans. Intelligence has reported that Riptide has finally developed his Tuna-Matic, a device that turns living matter into a marketable delicacy. Riptide is fast becoming a rich villain by selling his "Tuna" on the black market as a trendy food for the filthy rich and powerful. Riptide has hidden himself deep within underwater catacombs off the coast of Australia and has surrounded himself with deadly protection. You will come face to face with many of Dr. Riptide's creations and traps, so be prepared. If you reach his lab, Riptide will be waiting for you, and he will have no regrets shipping you out in a tuna can!

A side-scrolling DOS game set in the Great Barrier Reef.