So let me see if I understood right: You pay for the game, as if it is a normal retail game/ release, but they lock game modes behind a paywall, and that mode being the campaign?
Good lord, I hope this game fails. I hate these practices.
My (locked) thread about how difficulty should be a decision for the developers, not the gamers.
https://gamrconnect.vgchartz.com/thread.php?id=241866&page=1