There is of course the new bad guys. I give these two big thumbs up. Also included are two movies. So you may want to move it somewhere else when your done. They don't have any sound, but they look really nice.
Architecture is good.
I didn't see any problems. Gameplay flows together. There's nothing that will keep you wandering around too much, save for one possible part, depending on if you do one thing first, but, it shouldn't be a problem. Ammo was never a problem, but health got low some, and I died a few times, but it didn't get annoying. Weapons placement isn't really an issue, because you get your ammo from the guys you shoot.