The main goal is to try to get a car across. The player who gets a car across to the other side of the screen gets a point. Who ever gets 10 points first wins the game.
You can build cars from the tetris blocks, by rotating them and placing them down. The blocks can't overlap, but they must touch each other. There's a timer that ends your building phase, what ever you've build will land on to the playing field and hopefully will start driving towards the other end of the screen. When you're in the simulation mode, you can drop bombs by pressing A button, if you have any.
You can get bombs and other power ups from the crates that fall from the sky. If your car touches the crate you'll get a power up. Usually it's bombs, but it can be something else as well.