merry christmas with vocaloid

I know you put a lot of effort in to this piece, but somehow it look discrete, let me point out the reason:
+ BG: if the Char + Sky alone is ok, but with the additional section below the tower and the city, it looks horribly wrong! I suggest you add more tall building to prevent the feeling the city is too flat.
+Skin: Try to clarify the bright side and the dark side, and try to choose skin color brighter, especially Luka, she looks like an African.
+ Mouth: I believe you can see Luka's ABOVE teeth, not UNDER...
I appreciate your effort, and hope you'll improve in your next artwork!