Point and click mouse, use the in game tutorials.
Q to quit the game and go back to main menu.
R to replay current level.
M to toggle music.
S to toggle sound fx.
If you feel this game is too hard, you should read and follow the game tips by clicking "Game Tips" button on the main menu screen.
This game is very simple. Just press cannon to shoot the ball. One Cannon, One Bullet, One Chance.
Your main objective is clearing all balls on the screen by shooting them with cannon's bullet to finish all of 70 levels.