The Simpsons: Virtual Bart Cheats - Sega Genesis

Water slide: Correct tube
When you are in the water slide game, on the top under the score is a line with a fish. Before the water slide separates into two, look on the bar in front of the fish. There will be a colored dot there. This tells you which color tube to enter. If it is the purple dot, go into the purple tube. If it is the blue dot, go into the blue tube. If it is the green dot, go into the green tube.

Tomato round: Extra time
On the tomato round, when Principal Skinner is bent over and shaking his butt, throw a tomato at him. If you hit him, you will get ten extra seconds.