It looks cool however I've seen better ones from you. You should work on that Volcano, add a bit more of terraforming for example. It goes from plain to a giant steep mountain which isn't really realistic in my opinion.
If we’re going for realistic;
I feel as though it’s unrealistic to have a beach either: all around the island, or of, at least, the same width.
In regards to the post:
First off, keep the lava. #ProLava
Another adjustment I’d think would look really cool, is if you would add trails (even little) behind the boats. As well as more grass here and there, more in the forest (not too crazy).