So, on Hard mode you don't get the Masters? That just plain sucks. Oh, let's defend the castle but you have no upgrades left to fight the immensely strong hordes. Bummer. Let-down for the otherwise nice game
There should definitely be an upgrade "zombie intelligence"-chase down last person on map instead of aimlessly walking in circles in a corner with my 10 brethren
Having a lobby would greatly enhance the experience. I think many people leave because either they haven't joined the room with the right map, or are n't playing with people of the right level/type. Being able to see how many players, the type of classes are playing, and the map from the lobby would quicken the grind of looking for a room with the right map and players. It's been too often that I join a room of 3 people, and left to be the last one because of the leavers, though the quick match option should still be available.