Not bad, even though it isn't your best.
It may not be the best mixed media drawing around here, it's still good. I like how you drew it in charcoal, but the design is a bit odd. While the background may look like crap; it is not the focus of this very piece. However, it feels a bit too much like Ultraman (not that it's a bad thing). My piece of advice: Keep Practicing and maybe try colored charcoal.