Hi! there is a problem with the stars, i think. You made an extra class for stars. It might be just more easier, if you import the Color class in the "World"-class with: import java.awt.color; You have to write this phrase in the line under import java. greeenfoot*; And then you just write in act(): GreenfootImage i=new GreenfootImage(getWidth(),getHeight()); i.setColor(Color.black); i.fillRect(0,0,getWidth(),getHeight()); i.drawImage(0,1,getBackground()); //if it moves to slow, you have to change the 1 if(Greenfoot.getRandomNumber(10)<=2) i.setColorAt(Greenfoot.getRandomNumber(getWidth()),Greenfoot.getRandomNumber(getHeight()),Color.white) setBackground(i); then there wont be so many Datas and it wont break. If an other user has a better idea, you can use his possibility. ;)

I allready checked! :D And I managed all Levels! Its a very nice game! Good work!