It's not very exciting. The character design is neat, but as I understand it's not your own character so you don't really get any points for simply rendering someone else's design, though the technical aspect of that is fairly good. (Surely not everyone is equally good at rendering someone else's art.)
The big problem is that even as fanart, the imagery is not very dynamic: there's no background, no sense of depth, no sense of motion or intention, and no real perspective. Everything just looks kinda... flat, emotionless. Experiment with changing angles and depths, making some things closer to the viewer than others and give a sense of space that the character resides in.
Other than that, even though those are big things, you're on a good path with your technical skill. You just need to refine and expand it to produce more dynamic artwork, and of course hopefully to create something original as well. ;) Keep it up.