|Mr Khan said:
I would deem it a subgenre of the MMO, at least in terms of how to define the multiplayer itself
It is kind of like that, but it doesn't really do it justice. MMOs are big, persistent worlds that are shared by all players.
With these games, you get a much more directed multiplayer than MMOs offer (for now at least), not to mention you can play offline.
Maybe we should call it möbius-player games, because they are both multiplayer and singleplayer games at the same time.