After the Fall added 2 new maps, which is has always sorely needed more of.
>Hospital - Fairly standard map, has a nice midway defence setpiece and an outdoors hold at the end.
>Subway - No saferooms and it works very well. Sacrificing inventory space to carry cards all the way to the end was painful. Cramped and difficult with a lot of horde spawns that come from all directions forcing you to move and shoot.
Neither map has a boss, just lots of snowbreed and special enemies.