Sirius looks like he's been out on a night on the tiles! He's very rock and roll, isn't he? Those red eyes.... whew! And yet, you can see the canine in him, especially in the thumbnail. I don't know how you artists do it, but it's just wonderfully elegant to me.
No probs. I love your Snape as well. You just capture him in all his emo glory. Brooding, sullen, distressed, exhausted. I love your Snape. There are some monumental artists here - you are one of them.