I ceded to using some AA in this piece instead of dithering, which is what I typically prefer to do, or no AA at all. Definitely agree it's the worst part. The background AA failures are because I was trying to get some kind of effect going (can't remember what now) and was simply too tired of working on the piece to put much effort in. 
Thanks a bunch for the rest, though <3
 

I like the placement and the style. It's somewhat flat tone mixed with the more realistic bone texture makes it look like some sort of rad 80s poster. I also think the color choice was good; there's some "clashing" purples on the purple jacket but I think this gives it a cool "ultraviolet" look.

I think the antialiasing is the weakest point in this piece. Where the deep purple (644473) background mixes with another color like the sky or the pink missile trail, the antialiasing shape doesn't seem correct, like when it's a whole 2 pixels wide or when the antialiasing color disappears but it looks like it should still be there.