He doesn't have the cables connecting mask to the rest metal parts. If I was you, I'd make also minor changes to the mask part, to make it look more sinister (aka sharp edges like on
http://images.wikia.com/oddworld/images/2/23/Slig.jpg ) - beside these two, it's great
EDIT: Just noticed that in the picture I posted slig's mouth tentacles end much sharpier
