The game is extremely simplistic and very easy to get the hang of as soon as you start playing. The game essentially revolves around two characters standing on a number of platforms separated by a wall. Each character has a cannon strapped to their back, which is used to launch balls over the wall, onto their opponent's side of the screen. If the ball isn't caught by the other player and lands on the top platform, then that platform disappears. When all of a player's platforms are gone, they lose.
Regarding firing, the fire button must be pressed once to start the cannon moving and then again to fire a ball. If the button is held down, then multiple balls can be fired at once, although you must be careful of the recoil this causes.
For the single player mode, there aren't really any levels, but a sliding difficulty meter. Anybody who can beat the hardest difficulty is truly a force to be reckoned with.
The only section of the game that may require any explanation are the power-ups. The game begins with each player having a single gray ball. There are power-ups which when hit divide the ball into two. There is also another power-up that increases the size of the player who hit it, and decreases the size of the other player. There are two power-ups that change the speed and colour of the ball. Black makes the ball move much faster, while green greatly slows the balls down. Unfortunately, can disrupt the flow of the game somewhat, especially if you have a large number of green balls in play.
As for the controls, they're also very simple, using only 3 keys. Player 1 uses Z and X to move left and right and S to fire while Player 2 uses the arrow keys. Unfortunately, this is the game's main weakness. The controls for Player 2 are much better than Player 1's. When playing with friends, I generally say that the better player should be Player 1, creating a handicap of sorts.
Speaking of multiplayer, this is where the game's real beauty lies. Although single player is very enjoyable, the game really comes into its own when played with friends. The superb messages received after victory just go to make winning a hard-fought battle that bit sweeter.
I've played this game a lot, and found some useful tips and tricks to assist you in beating both the harder levelled foes and to help you face your friends. Firstly, you can catch balls while firing. If a slow-moving green ball is coming towards you, then you should position yourself where it's about to land and then fire, catching your opponent off guard. Secondly, the easiest way to collect pick-ups on your side is to stand directly under them and press fire once. When the cannon reaches a 90-degree angle it fires automatically. This is particularly useful when splitting balls, as you can catch both of the balls easily if you just remain where you fired the ball from. Lastly is a great move devised by a friend of mine. If you have a large number of balls in your cannon, then move your bug to stand as far to the outer wall as possible. Hold down fire till all of your balls have been selected. Then, leave the cannon so that it fires directly upwards. Although the first ball will go straight up, the recoil will cause the rest to hit the outer wall, sending them over onto the opponent's side, and leaving you with around two balls to catch on your side.