[LunaTheHamster1]

wow that looks a fabulous cage. The only thing I would be inclined to do if I had a set up like that, is to build the substrate up higher. If you have the height (which you clearly do) that is what I would be doing. Although it may be quite high in the middle where the tunnel bit is - it's hard to tell by the level the photo was taken at . Otherwise I think your hamster is one lucky hammy.

I didn't realise there were more photos. the one at the bottom shows the rocks, I would just make sure they aren't going to move and your hamster potentially get their paw trapped. I personally place my rocks flat and don't pile them up. From the photo it looks like the big ones may not be going anywhere, but it's the smaller one on the top that I would be worried about.