Girl is cute. The man looks like someone who's asking to get his ass kicked. Don't know why, just the feeling I get.
But in all seriousness I like them and since you're going for portrait may I suggest you either rotate the heads or the light? I think you're going for a butterfly effect but it looks relatively flat. It'd be much more interesting to let the shadows show the forms.
Personally I'd pose the heads instead of changing the lights. That way you avoid the dead look of the eyes. If you prefer to change the lights though, I'd have the eyes point at an empty either at the top right or bottom right of the portraits, depending on the feeling you want to give to the characters.
I'd give more details but I'm on the phone at a break from work so I really can't. If you want me to, I'll be able to do so in a handful of hours from now.
