I agree with Free Full. There, now that compliments are out of the way I can be purely negative =D

First of all, regarding hands, I recommend knuckles. The hands, especially the girl's right hand (as in, her right) seem to suffer from a lack of bones. You can usually get away with skipping a few, but try to at least define the joints that connect the palm of the hand to the fingers.

Oh, good job on making her recognizably female, though =P. Her her hip shape looks a bit wrong (too thin?), but it's hard to tell since it's dark and the picture pretty much ends there.

Also, her horns don't look even. By the looks of it, one is coming out of the back of her head and one is coming out of the left side. Realistically, since the left side of her head is in front of the guy's face, it seems like her left horn should be in front of his face, too. That or her head should be more tilted towards the "camera".

On the guy, this is super-minor but I think his bicep should be bulging a bit more with his arm bent like that. It's almost flat there, despite lifting his forearm up. Also, his deltoid looks tensed even though it's not doing much of anything.

Oh, and his hair. How does his ear fit into that? It looks like it was just put overtop the hair.

Critical enough? ;D