When Venom is "whole", he looks good, but when he peels back part of his face, it's like a human sitting inside a fleshy exoskeleton, and the mouth/tongue is incongruous. In comics, there's no need to show the guy's head/face when he's Venom, but in the movies, I guess people want to see the actor, so they show his head/face, but it ruins the creature IMHO and makes it appear to be a flesh exoskeleton.
From the trailer, the hero/villain dynamic looks similar to that in Iron Man where two guys in armor suits square off, except here it's two guys with symbiotes.
Totally agree that casting for Venom in the earlier Spiderman movie was terrible. Venom didn't choose a friggin hipster in the comics.