Very nice so far. One thing you may want to consider though, set the paint order.
Right now, the ground objects are in front of the people. It's easy to fix though. Just go to your World class, and in the constructor (Just below where it says super(number, number, number)) add the line - setPaintOrder(Player.class, Ground.class);
2011/6/11
2011/6/11
2011/6/13
2011/6/13