Move your mouse to move the mushroom. Don't let your mushroom touch the black or it will be reset. Don't let any fruit touch the bottom or you will get subtracted points. To get the fruit to bounce back up touch the mushroom to the fruit. You get points when you save a fruit from falling to its doom.
This uses a lot of pick randoms and set y and z blocks. When you see that you've lost 100 points don't think you did something wrong. The game does it on purpose at random times.