Second; you could add a little hut maybe some clouds or things such as a blimp to fill up the empty space you have at the moment around the islands. Another suggestion is adding a few smaller islands with other props on them s.a a cactus, possibly a waterfall falling down or even a hill.
It does depend on what kind of purpose this map will have; decoration purposes, swordfight, RPG etc.
If you do want to fill up the islands I’d suggest looking at some refference images on the internet.
It’s quite simplistic since it’s not much needed within the terrain. The island looks small so I wouldn’t expect a bunch of details covering the entire terrain part.
You don’t want to overdo the details if you plan on adding sorting objects; i would recommend adding things that fits the overall design. There is little details around the area, to give the scene a more decent feel. Why not place dried trees with dusty rocks just to give the terrain a little more depth. Some different shapes of rocks/trees and dried grass would also make it fit the style.
My small recommendation, would be just adding little details, and making vegetation that’ll fit the scene desert places don’t feature little to no details it just needs a minimum of props I’ll look at real life images to gather similar ideas and see which ones look good to you. Otherwise you could just about add anything related to a (desert Island).
You could make the terrain less flat with some mounds of sand or more rocks scattered about. Maybe something like a camp or an oasis would look neat too.
Lots of clashing styles, the islands are ok but id try and continue the blocks so it comes to a point instead of ending with some thin bricks, also maybe make the ones with tents larger so the tents dont get in the way of the zip lines, also the fire guis are ok but they ruin the vibe, maybe just make it click instead of using a gui, also theres lots of free models, Im not against free models but when they dont fit the style they stick out, aside from those things youve got the ground works for an amazing showcase
Add an infinite sandstorm going on, not so much that it lags the user but like some sand blowing. Also for the rusted car tilt it downwards into the sand.