As I did to the back part. I think it could use a bit more depth as it looks confusing to my eyes when looking at this: The rest of it I think looks pretty nice, very ICE'y feeling to it. I also like the stone parts. But yeah, try to differ the randomness of the cloudes, I can tell you simply copy and pasted a simple image to make them longer, something like this could work though: Just some suggestions. Edit: Is Sonic's eye supposed to be RED tinted? If not, you should use dark grey, that sometimes works for eye smoothness.