I didn't have time for much feedback earlier since I was at work, but darn you for working so fast! I do have a few comments on the linework of that face... Like Val says it's a difficult pose to pull off. And it seems to me that your linework hasn't quite decided on which angle it's going for.... If you want us to see as much of the face as we do, we'd also see more of the bridge of his nose. If you want the pose to be as extreme as the nose suggests, we'd see considerably less of his forehead. Also it seems to me that the upper edges of the ears join with the jawline, rather than the lower edge.
I did a quick scribble over, first to show how I think the chin would curve, the ears attach and more of the nose show, and then I did a sketch on top of a stock photo of a similar pose. With that person's shoulders in the same place and same size head, the features match (position of eyes, nose, mouth) but end up much higher, with considerably less of the forehead showing.
I'm sure some of these things would be considerably less visible when painted rather than drawn as lines. You have a very vibrant palette most of the time and your finished work looks polished, but I do think you could practice anatomy a bit... Not just this face but I think it's evident in the bodies of Harley Quinn and the alien as well.