It's pretty impressive, considering that it's made with freeware. The collision detection is some of the best I've seen, which is impressive since that's a tricky thing to do right. Moving up the hills and into the caves was a nice touch.The only problem I noticed was a lack of direction. After I got the first ball home, I had no idea what I was supposed to do. After looking at the code, I was pretty sure there was more... just had no idea what that 'more' was supposed to be.