You start out at the bottom of the screen next to your base. Enemy tanks will appear from one of three positions at the top of the screen.
In each stage, there are 20 tanks in total you must defeat in order to advance to the next stage.
You can fire in four directions. Most tanks only require one hit to destroy them. One type of tank requires four hits.
If one enemy bullet hits you, you lose one life. If your base is ever hit by a bullet, the game is automatically over.
Bullets can destroy walls, whether they are fired by you or the enemy. It takes four shots to break through a standard width wall.
Enemy tanks that flash red provide power-ups whenever hit. The power up will appear randomly somewhere on the screen.