Been playing it awhile now that its in open beta, some thoughts, excuse the LFD comparisons, but its pretty much the same game with some new stuff.
Cons:
WAY TO FRIGIN DARK, yes I understand it night, but taking its spiritual guide (lfd) who used light amazingly well (flashlights, way points etc) this game makes poor use of lighting, its often hard to see whats going on with no way of solving it. I know i could crank the brightness, but thats not how you solve a game problem.
Needs work on movement/fluidity of characters and mobs. its not bad, but again L4D has it down well, this game is so-so. Hit boxes are not good, and melee combat feels "off" because of it.
rats is rats is rats.. with the dark palate and such its a bit hard to really see any difference in rats. Some have bright colored accessories (poison, flame) but others... one thing that Made LFD work was specials, and the distinctness (sounds, etc) to warn you. This game is poor in this area, in the end it feels like a horde of rats, the worry, the sound clues etc are all gone. Now the game does make up for some of this (see pros)
Artwork, its Warhammer so i understand the artwork, but it really gets to feel very 'same old thing" shacks, alleys, stairs, again, how do you change this up?
PROS:
Long missions, love this, i just hope we don't get the WOW crowds (instance takes a few seconds to long and they quit out) where as the game gets older people cant take time to play, just want the end result. While I would guess as time goes on it will seem shorter, right now a full mission seems 2-4 times longer then L4D which is great in my book. They also put items in hidden areas and encourage exploring which breaks the group up, and makes the game more exciting. And many items are worth having, or just plain needed.
Classes- Very nice twist, not 4 people with same guns, each has abilities, Ilike this very much, while its not a HUGE gameplay difference, you do need to learn each class to play it well.
TEAMWORK!!!!!!!- this game has this RIGHT in spades, LFD will punish the stragglers or rushers, but if you are good you can handle it. Not this game (or not till I am much better). Stragglers will be snatched.. there is no maybe, they WILL!, so not lolly gagging around. Rushers will be pounced.. get out ahead all alone.. you will be uncapped. This game really shines with good teamwork. Forums are already full of "to hard" statements and from my game time, its just the SOLO, F-the group players who are having a rough go of it. RUSHING hard (a valid LFD tactic, almost required for hardest level) is punished in this game. Seems the devs actually wanted you play the levels, not just run through them.
Specials: I like that they are not so easily countered in this game. In LfD you can almost always complete a map and never have a special incap anybody if you are good. The Specials in this game are to force Teamwork, so they are quite successful, but easy to take care of .
LOOT: its got a level loot system, nice for replay. As i haven't looked at it to much i wont comment on it other then to say I like it.
Overall I really like the game, its a nice LFD change up. I think its a great game and needs a tiny bit of polish (less dark) and bit more polish on player/mob interaction.
As is, its good, almost as good as LfD was when it came out. I like it.