Somewhat of a review:

The good
- It's free
- Graphically pleasing
- Its super simple to pick up and play
- Unlocking (and using) weapons is very fun
- It's coop

the bad
- Short campaign
- Perhaps somewhat under-utilised classes?
- Not tactical enough?
- Perhaps too fast?

The ugly
- Mmmm, don't really have an "ugly" comment

I'm hopeful that user-created content will appear. It's a fun killing game, in my opinion very similar to something like Diablo... well... minus the item collection, which I suppose is kinda central to Diablo. Still, a good killing/destruction game.

I enjoy this but... it does seem short. And it lacks something but I am not sure I could put my finger on it. I seem to get bored in it easily. I dunno you know you will have swarms, and I guess it seems a little repetitive.

http://store.steampowered.com/news/4238/

AI director added, and crazy difficulty levels.