One note is that in the Origins style (which seems to be where you got drawing the head from), or in the way you drew him, it's as if his mouth is facing directly sideways, even though he clearly isn't. See how the inside of the dragon's mouth is visible? I think it would be better if Glombrox's was too.
It's alright in Origins since the whole style of that game was kinda funky and the artstyle didn't abide by the laws of the third dimension, but mixing the two styles makes Glombrox look unfinished.