The best is the multi-ball, giving you two more balls. The worst upgrade is the hearts - a broken heart will destroy your bat but a full one will give you a new life, and sometimes, in the heat of battle it's hard to tell which is which. They range from changing the speed of the ball, the size of your 'bat' (the controller), giving the bat weaponry, and more. To make things even more fun are the various power-ups that come from breaking the scene apart. The graphics are so cheesy that they're absolutely adorable.
There are sometimes little animals, and when you hit them they go flying off into the sky. Each 'level' is a little scene depicting something - a car being driven, a beach scene, a zoo, etc. Instead of beating up a plain wall of bricks, however, you're dealing with something that looks like 'Legos for Children' Meets 'You Did What?'. The basics of the game is older than BFG itself - it's based on the ancient game of 'Breakout.' You have to keep a ball in motion or boom! you lose a life.
Perhaps it has some hidden message to make you completely addicted to it. I have no idea why I cannot stop playing this game.
