As I am late to the previews and can't be bothered to read threw all in one go, what are the general positives that the journalists mention, and what are the worse?
Previews have been all over the board, but general pros are the atmosphere (most said very similar to Aliens) including the lighting, the xenomorphs themselves, the drop in/out co-op, the standoff scenes, and the ominous return to the Sulaco and LV-426. The marines were also praised for being foul-mouthed and realistic, bringing back a lot of that special Apone magic. Sentry guns are in, as well as door welding (but only mentioned in one preview.)
The crusher is new, sounds/looks like a sort of Praetorian that rams the marines and is bulletproof. I think the given explanation for this variant was the heavy radiation contamination from the atmosphere processor. Power loaders are also playable, and the marines apparently weld flamethrowers and pulse rifles to the arms.
Also 3 acts confirmed, Sulaco, Hadley's Hope, and Derelict (!)
Weren't really a lot of cons, and some of the previews were rather strange as they dinged the game on things other previews had praised it over. Mostly just early development issues and bugs, but I don't remember reading anything really negative.