So, I just installed it and I have to say that they look really good.
I must also agree that the penguin has something "disturbing", pherhabs it's this "huh?" look of his eyes? The Icons don't look..well...refreshing. You could make the Folder-Icons a lillte bit more 3D, and so the other Icons, too. The Mozilla-Icon looks really flat, and I think you should make a Icon for the Control Center.
Conclusion: Try to make them look a little bit "fresher". But they are very good by now. I'll use them for a while and then I'll check back