[callesgg]

Some islands look a bit unrealistic.

With swamp areas sticking out i the sea.

Waves would remove such things in a short timespan.

[viraptor]

I disagree. We know nothing about the height at this point. It could be anything between a big, flat beach (http://hd.wallpaperswide.com/thumbs/beach_island-t2.jpg) and crazy cliffs sticking out into the sea (https://upload.wikimedia.org/wikipedia/commons/d/d1/Cliffs-O...)

Without a scale and a height map, almost no shape is unrealistic.