Pros:

+ challenging
+ quite good bossfights
+ i love the flighing jockeys

Cons:

- third chapter a bit to much special infected
- you nearly have to be a group of 4 because the bot f**ks up often

Conclusion:

for the first time after ages it was very funny and challenging, i have to play it again when we are a group of four.
awesome. i think a must have