One more thing: you are adding the rocks into the world at random locations (which is fine), but it would be good the make sure that one does not start at (or intersecting) the marble (or even close and moving toward -- which would be harder to check for). The best way is probably to start the rocks near the edges of the world. Maybe something like [code]int rockX = (Greenfoot.getRandomNumber(getWidth() - 200) + getWidth() / 2 + 100) % getWidth(); int rockY = (Greenfoot.getRandomNumber(getHeight() - 200) + getHeight() / 2 + 100) % getHeight(); addObject(new Rock(), rockX, rockY);[/code]

You could add a scoring scheme to it (maybe a point for each 10 act cycles survived, or something like that). You might want to slow the rocks down a bit to start and as the score increases, slowly increment the speed of the rocks to make it harder.

You should change your description. I was expecting them to come from the 'right' side of the screen, and OH NO, they are coming from he LEFT!! WATCH OUT! (Good Job, anyway).

Posting the scenario with source is helpful in getting the help you need, but it would be wise to start a discussion explaining in what way you need help (being specific, one problem at a time). Just saying you need help would not be productive. So, say something like, 'I am creating a break-out type game and I am trying to make whatever do whatever' or 'I cannot get such-n-such to work. Ive tried so-n-so, but to no avail, and Ive tried this-n-that, but still no-go. My scenario is where-ever called what-ever, supplied with source. Could someone please take a look? Thanks in advance.'