The first one needs to go a little lighter on the horizontal lines to the upper right side of "The Mouth" and also the white spot on "The eye" Other than that I think it accomplishes what you were trying to do.
The font that says "venom" is not "rough" enough, as 'HaVoK' said.
But honestly. I have seen so many attempts at making venom-signature that failed.
This one actually owns!