I adore your cartoon-y style! It's really beautiful; there's a lot of emotion in your facial expressions. My favorite of your images is the speedpaint, which I think came out lovely. I really should start doing speedpaints, a few have recommended I try them but it keeps escaping me when I'm in the mood to draw. XD;
Oh, I've seen those Avengers buttons elsewhere before, but don't remember where. Thor is my favorite Avenger and I think you did a great job capturing his personality!
I'd recommend working on your angles a bit to be more "dynamic." Other than that, I'm noticing some of your faces seem to be a little stretched in the cheek area; not sure if that was intentional or not, but I wanted to point it out.
Great job, I love your work!! Please keep us updated. =D