this needs so much work I'll just abstain from giving a rating
please try harder to make islands non-regular in all forms, outline, surface terrain/elevation, and cliff edges. having a simple square flat no-overall-shape baseplate on top of regularly duped ramps and incomplete corners does not count as an island
I highly advise you learn to really try to build (yes you may be inexperienced but at least put some effort into making it better) then go read my terrain guide.
Don't let this post discourage you; I'm not trying to flame, just to say you can do better than this, if you put in that extra effort.