The black hole at the bottom of the ocean is hungry! And she has very specific wishes too. Bring her the correct types and amounts of sacrificial plankton before your opponent does and before she changes her appetite. Beware of the other fish though; they can (and will!) steal the plankton they like off of you. You can also use their kleptomaniacal tendencies to your advantage whenever you have accidentally collected too much plankton of some kind. Either play for a fixed amount of time or race your opponent to the first to get a certain number of points!
Player1 uses the WASD/ZQSD keys to move around, while Player2 may use the arrow keys. To deliver innocent plankters to the great almighty black hole, simply bump into her. Good luck!