Well I did it. I extended the 3rd level. I'm finished. No more levels. They love it of course. My husband wont speak to me (tough -), he will get over it. The only thing I dont like is that by adding levels you are making the level underneath it dark. It makes it depressing looking. I didn't build the levels completely around the cage. Cage is 2x4 and levels are approx 1 x4, but still, I dont like that its dark under neath each level. ANYONE ELSE HAVE THIS PROBLEM IN WHICH IT BOTHERS THEM?