Managed to snag the game early. My impressions so far.
Definitely not the prettiest game on the market but alot of the times your running up buildings or jumping at good speeds so its not all that noticeable. The amount of people on screen at a time is pretty nice to see (especially when you see them all running away screaming).
At times there can be alot of action going on at once. For instance a building might be blowing up, panicking drivers and civilians, dozens of foot soldiers shooting at you, helicopters and tanks firing rockets and the occasional monster. At these times the game seems to hold up pretty well. there is the odd slowdown here and there but its not common and doesn't last long enough to drag you out of the experience.
I remember an interview with the developers from last year where they said they could pull off areas that looked like a scene out of I Am Legend. At the time I didn't believe I would see anything like that at all, but to my surprise they more or less nailed it. I was running around a heavily infected part of the city. All of a sudden I noticed the streets below me. Some buildings were on fire, smoke was coming from a few directions. This gave the sky an eerie flame look which which changed the lighting of the city area. The roads had deserted cars placed in a believable way while around them dozens of bodies were lying in the streets. It actually put a chill up my spine.
The gameplay itself is alot of fun. The running, jumping, fighting feels very nice and the animation is pretty well done. There are a couple of problems with the camera now and again. Like one moment your running up a building and all of a sudden it does a 180 causing you to fall. Thankfully it doesn't happen too many times so its nothing serious to worry about. The soldiers put up a good fight. At first its just assault rifles they fire at you which you easily laugh off. Progress a little further and they get more serious with missile and grenade launchers. Not to mention one soldier can call in 2 choppers which are really hard to shake at first. You get about 3 seconds to stop him from calling them in. The monsters are pretty average. You have your everyday slow zombie, to more agile and sometimes carrying weapons, tentacles that come out of the ground (real pain when your in a tank) and big bear like things called hunters which almost always cause you problems.
The main missions don't break any new ground. You have the go here, protect this, collect this, follow this type for the majority. They are alot of fun to do most of the time though some go on alot longer than they should (for example you need to protect a building from oncoming infected for 4 minutes. Should you fail you have to do that part over again).
The side missions are a good diversion and a good way to save up for the skills you want to unlock. There's about 7-8 different types from consuming selected peoples memory in the time limit, a push back style mission where you team up with infected, gliding where you have to land in the middle of the target, checkpoint race and a few others.
All in all this is a really fun game. One of those ones that put a smile on your face when you pull off a cool trick or dismember a pack of soldiers. I would roughly say that the main campaign lasts around 10-12 hours but there is plenty of diversions after that to keep you entertained. Definitely worth a look in