This game is very good. The sounds of the weapons are awesome and really makes it feel like they pack a punch. Playing on the harder difficulties can be amazingly difficult even with a group of people who are working very well together. I'll be getting this game probably in the Spring when I have the extra cash, though finding 20 USD really isn't "too" hard for the most part.

I personally don't recommend the custom maps like the one in the video. Most custom maps, including this one, that I've played have some design flaw which makes certain areas absolutely perfect places to defend from. In that level for example there are two main rooms. One has only one entrance and the other has a front entrance and a back entrance which only the crawling ZEDS ever use (only one person ever needs to guard it). The strategy is to get in one room and just wait for the creatures. Since all the creatures must come through one entrance they are easily defeated. Which, in my opinion, takes the fun out of it and turns the game into a grind (I played with an entire group of of people I didn't know on the hardest difficulty and won on that level without pretty much any communication from the entire team). The stock maps have good defensive locations, but with more ways for the ZEDS to get behind you and breach defenses or merchant spawns which take you far away from those good defensive spots with no hope of making it back before the next (ever increasing) wave of ZEDS arrive.

Though the custom maps I've played have had these issues I'm sure there are custom maps out there that are very good. I'm pretty sure the new maps from the "expansion" are user made maps that the devs liked so much they added to the game.

The only thing I have against the game is that they don't have a party system. I remember playing this game on a Steam Free Weekend special with two of my friends. It took about 30 minutes to get us all on a server without it filling up before everyone could join. Since there are only 6 people to a team, and if the server doesn't allow spectating, it can be very difficult to get your group on one server (unless you have the capability to host your own, and if you do you better have 5 other friends since you can't switch the server from passworded to unpassworded in game). And even if the server allows spectators, your friend may have to wait a long time before one of the other people on the server decided to leave.