Faces and expressions

I was sketching faces last night. I think I'm not bad at expressions and i really enjoy them. It's pretty damn neat how with just a few pencil strokes you can convey emotion. A reminder, clicking on the image will give you a larger picture.

1) that was an attempt at Wolverine and I think the nose is right but the face is too soft.

2)She didn't get pupils because she looked a little evil without them. I like her.

3)I just like that one a lot.

4) An attempt at Northstar but his chin was too strong.

I think the men turned out okay. Do the faces show something of a consistent style though?