Hey there!

So I'm not going to split my review into three sections.
What I want to say is that the effort you've put into this build is amazing. You've worked hard to get the curves right, make the floating islands, make all the cliffs.
The problem is that it's just.. too simple.
I think you're going to need more things on the islands, little ponds, structures, trees, custom flowers etc.
That'll cover all the basis.

Good luck!
- Dutty :3