Sweet! I saw you on Drawstick, but never realized you had a deviantArt account!
I like the overall look and feel of the piece! It has a sort of "dynamic/cartoony" feel to it, and its awesome! I also like the lighting, the textures (especially digging some of the subtle textures on his cape because, well, I'm nerdy like that!), and I like the sort of "scribe-ish" sort of feel you pulled off with the background!
The only things that are bugging me (and this is admittedly nit-picky)is that his feet don't seem to necessarily be on the same plane. His right foot seems to almost be on it's tippy-toes, and also looks like it's a bit farther down than the other foot. And also the cloth hanging over his crotch also seems to be facing more towards the front (or towards the viewer) while the rest of his clothes are facing at sort of a 3/4 angle. Again, it's not uber noticeable, but just something that caught my eye.
This piece really caught my eye in my watched deviations. I think its all pulled together really well... I like how you did the background, from the texturing, to using just the lines of the character rather than the color version, to the text. Its the kind of "simple" background that actually has a lot of really nice design elements going down that I especially enjoy.
Loki's looking great! I was kind of put off when they made the latest incarnation of him a woman, but I probably just wasn't used to it that way, especially since he was always portrayed in Norse myths as a male. Anyway, can't complain by Marvel's treatment of the character. Male or female, he'll always be one a bad-ass character in my book.