The only major issue with this game is how empty it is player wise, thankfully I found a community that organizes games sometimes and played a couple of rounds with 10 players it ended up being a lot of fun, I would strongly recommend it for those that likes co-op games AND have the chance to organize with a couple of friends or find a community to host games.

Being more specific with some points it seems that some of the unlocks and feats requires a lot of grinding, which again if you cannot organize a play group that easy, getting achievements for this game will be a very hard task to do. Another thing is that the levels are very different when you play with 3 people compared to 10 people, so you may want to vary the amount of players you get every time or the levels will start repeating after a while.