Swim as far as possible, while trying to avoid the procedurally generated rocks and jellyfish. Eating small fish increases your health and eating crabs slows down the ever increasing pace of the game. There are a few secret codes that can be entered for bonuses during gameplay, see if you can figure them out from the hints in the game. Click the mouse or touch the screen to make the fish swim down; release to swim up. Smack a jellyfish on a rock to shake it off if one sticks to you.