The player takes control of a character named Becky. The game is set in the future and the world is primarily surrounded by water. There is a small patch of land called Terra. Terra is the only land. The player must prove their worth to be accepted on to Terra. They do this by proving their skill as a submarine commander and destroying enemy vessels.
Becky's version features different characters, items and boats to Matt's version. These are logged in a device similar to a Pokédex. The battles take place against other ships. A radar view is used to help you guide torpedoes against the enemy. A large part of the game is text based with animated cutscenes. Two players can link-up with the cable to battle and exchange ships.