I think the angle of the reflection is wrong... What we usually see when people try to do those is that they just mirror the image from top to bottom, and that's what it looks like you did there. So the perspective looks wrong, despite the camera being so far away and at a low angle.
So, for instance, if the islands have depth, I don't think you would be able to see all of the features that are just on top of the grass. And you would be seeing more of the underside of everything.
The colors of the shadowed parts and the lit parts being so close in luminance also help (in a bad way) to the feeling of flatness.