1) I don't know if I'm missing something obvious, or if the offline practice is by design only the first level.
Is it mandatory to play online to be able to play different levels or am I missing the option to do it offline?
2) How can I join an online game? Whenever I join a game I join as a spectator with no way to join in the game, is it just my luck that I don't find an appropriate game to join or again I'm missing something obvious?
EDIT: I did what this answer suggested, but the first method (launch options) didn't work. I can see the levels but when I click "Create Game" nothing happens -- doing it with the console works ok.