Fishing Derby is a two-person competition to see who can reel in the most fish. You and your opponent (computer or human) sit atop two docks on opposite sides of the screen. Six layers of fish appear in the lake below the docks, and your goal is to catch 99 pounds before your opponent. The fish in the first two rows are worth two pounds apiece, those in the second two rows are worth four, and those in the last two are worth six.
Drop your line by moving the joystick up or down and try to hook the fish by moving left or right. Once a fish is hooked, press the button to rapidly reel it in, but watch out for the shark -- it swims back and forth gobbling any fish within its reach.
Also of note is that only one person can reel in a fish at a time; the first person to "hook" the fish is allowed to press the button. Otherwise, the fish moves up slowly, making it easier for the shark to grab. The difficulty switches determine how precise you have to be before the fish bites.