Really clean design, but too much color variation in the window lights.
The water reflections on the bottom are too rough and inconsistent with the clean graphic look of the top. They would look better with a more stylized, "illustrator" effect, rather than the jagged, inconsistent "shimmer" randomly applied.
You need a bit of a gradient fade, with an opacity mask.
You might also want to check out this Photoshop Wave Displacement tutorial - It might help your water reflections look cleaner than the ocean wave effect.
http://www.photoshopessentials.com/photo-effects/water-reflection/

Mossy, not only the reflections are rough and the window lights unrealistic, the moon also looks strange and such blueish, orange and greenish four pointed stars simply don't exist. There are no such flat buildings with glowing edges too and you can never see a sky textured with Petals Three Color.
Have you ever tried to paint like a child? It's difficult. Only children can do it perfectly...
I know that effect called displacement water, and have used it plenty of times. There is a plugin too. Can you imagine me applying a realistic looking water reflection on a cartoon style image?

Bravo Author!

Nice

I like the clean crisp shapes of the top part in contrast with the rougher shapes below. Nice work, author.