Nice clean style and all, but the skulls and other body parts look very cartoony. Not to mention the obvious lack of blood in an interface supposed to be bloody? As mentioned by others, the bags are very blurry compared to the rest, and of much worse quality. I am also unsure about the transparency usage, I don't think everything will work as nicely as you opt for. Lastly, those decorations on the bars in the command button box probably end up too broad, overlapping (or getting overlapped by) the icons in-game.
It's a great effort, though, and I hope you see it through. There's not a whole lot of custom UIs out there.