While playing the game keep another window open (it can be anything from an internet window to an IM window). First, maximize the second window. Then, just play the level in jezzball untill you beat it. Once you get the popup saying you have completed the level, click on the second window to bring it to the foreground (the jezzball window shouldn\'t be visible any more). Then just bring the jezzball game back up and when you click "Next Level". You should go to the next level, but the popup telling you you've completed the level should stay, you can click "Next Level" again to beat the next level without playing it.
During gameplay, press: