Filler is a lot like Jezzball - the aim of the game is to paint the screen by clicking on it. Instead of using lines, though, this time you're creating balls (so to speak).

Clicking and holding down the mouse makes a ball appear on the screen - the longer you hold, the larger it grows. To complete each level you need to fill two thirds of the screen with balls, but if any of the smaller bouncing balls hit yours while they're still being made, you lose a life.

So the trick is to hone your mouse-button-holding skills so that you can release the ball just a tick before a bouncing ball is about to hit it. It's harder than you think.