Photo 1 - Shooting the black clothes against the white bars and bright colors is a good idea. Not crazy about the tilt. I would have liked to see another, more straight-on shot or one taken at a lower angle.
Photo 2 - I prefer this photo, especially the muted colors. They contrast sharply with the blacks and really make the red eyes stand out.
The assymetrical pose is interesting, and the facial expression draws me in.
To put even more focus on the cosplayer, try straightening the frame (it's a bit crooked here) and move the subject more toward the top of the photo. Watch your edges - you cut off his foot and the edge of the jacket.
Pay attention to backgrounds. Did you intentionally leave the cherub painting in there?
It's a good effort, and I look forward to seeing more!
Private shoots available!