Two players play against each other using one keyboard. One player controls the ship with W,A,S,D keys and the other player sends attacks using numpad keys 1 to 9, trying to sink the ship. The numpad keys represent the game arena. There are three different attack types.
Attack type 1 - Storm: Press one key on the numpad and a storm cloud will appear at the location that is represented by that key. The storm cloud will slow the ship.
Attack type 2 - Wave: Press two keys on the numpad like you are entering a two-digit number. A wave will pass through the game arena in the direction of the pressed keys. The wave will sink the ship.
Attack type 3 - Sharks: Press three keys on the numpad like you are entering a three-digit number. Sharks will attack on the squares represented by those keys. A shark will sink the ship.