Use the mouse to move. Eat the smaller fish for points. Dodge the big fish and the shark. Eat the colorful flashing fish to get big for 10 seconds. That lets you eat the big fish, but no matter what, the sharks can always eat you.
Credit to @Shiftclicklearn for the art of the player, and just ONE of the little fish. The rest of the game I fully drew. And I DID do ALL of the coding.
