Not too bad mate, but there are a lot of flaws which is really ruining it.

The colors, they don't really compliment each other and relate to each other.

Contrast - There's too much contrast where the symbiote on his face is.

Text - Don't add text mate, it usually doesn't look good and is only added because you think it's necessary to add it when it's most of the time optional.
^Those three things are the majors, try to fix that up. Keep at it .