Aww, that robot's kinda cute. Sort of in a rusty Wall-E way. I really like your method of water color designs for your backgrounds, but are the white dots in the water supposed to be reflections of the stars in the sky? If so, how come there isn't a reflection of the moon? (I take it that we can't see the reflection from the viewer's angle?)
Not trying to nitpick here, just something I noticed. Overall great piece.