It looks great!
The piece placed on top of the rock looks to be a little sharp, you might wish to run your fingers over it again and sand/file off any of the thin edges.
If it's just placed in then you will find that loads of waste will get trapped underneath and cause havoc with your water parameters.
A friend of mine has theirs siliconed down with all the gaps filled in, it looks great! The silicone took a week to dry and cure, but was worth the wait.