Hello Muton, I have a few suggestions that might be interesting, at least I hope so.
First of all, consistency. Key to the development of your own style is that you choose not to do all possible things in one piece. It's good that you have two different fonts, but there's not need to have all different letters. The way you drew 'ART' is an example of how inconsistency leads to uncertainty about whether those letters are representative for something (A.R.T.) or seperate (AR T). I know only stupid idiots would think that but it sure doesn't look as good as it could if you just made them fit together.
Second, anatomy. Simply put: at least draw your characters in such a way that a total stranger to your art can recognize its head, body, arms, hands, legs and feet. And it's always nice to insert physics into your work; in this case the character would certainly not be able to stand straight with gravity pulling his upperbody behind his legs.
Nice character design, I love the helmet/mask thing he has before his mouth. Reminds me of Kakashi!
Be considerate. Think before you say something that is not positively building up the listener.