In all honestly, I'm not sure what could be added to make it look better. The float island at the start is... Tiles. Maybe added a rock or two to the bottom. Maybe some twigs or something. Add a tree perhaps? I dunno, a lot of brown is a lot of brown either way. Maybe you could use Front Item scenery here or there just for kicks. Maybe I'm just really picky, who knows. Although for real, the floating islands are really bland with almost nothing going for them. The underground area could have some stuff hanging from the ceiling to show off the trees are actually growing into the place. I'm not exactly sure of what you should add, but there's a few suggestions.
Edit: Because I'm feeling generous I'm actually adding some stuff to this level myself. I'll PM you the results.




