The first thing i noticed is that His beer is not only apparently empty, but you cannot see his fingers behind the glass. You can see the pool table clearly through the glass (and that should be tinted more yellow I think) and in the zoomed frame you can't see his knuckles holding the handle.
However I can also see that this is more about quick sketching rather than exact refinement, so overall I think it's quite nice. Not a bad character.
Character wise, he seems a little just like a typical biker guy, I'd like to see more of his story and history and what makes him so evil? A rought type, a "bad" guy yes, but no more evil than your typical biker tough guy.
Just an opinion, hope it's not taken in a bad way. I like his style and stumpiness, but I'd like to see him explored further.
I too noticed a lack of consistency in the transparency of the beer glass, alongside a lack of consistent proportion - the character sheet illustration shows him much shorter and with far smaller legs than in the actual image. The waitress's rendering seems confused and soft, the environment lacks a cohesive atmosphere and colour tone and the "tub of ice" the girl is carrying - what is it? An iced drink? A cooler of some sort? I cant tell - poor visual cues. Otherwise I like Snooks as a basic design, but agree he lacks a malevolent quality or history that can be displayed through better characterisation or attire/accessories.