We streamed FMF a couple of times and it never really clicked for me, at least not in the way that Rogue Legacy did. It looks like I wasn't the only one feeling that way, as the Cellar Door people did an interview with Destructoid recently in which they basically say the game was a big flop. It's an interesting read!
I think NieR: Automata best explains the differences. After you beat Nier, a system message from Square pops up saying. The game is not over, please keep playing. It's straight up explicit.
We hid that stuff in marketing, we alluded in the game, and it just bit us in the butt. I think we wanted to do something too different with the assumption that when the game came out, people would give it a full once-over. But honestly, with the amount of big-name games like Monster Hunter World coming out in January, nobody has the time. We sat on this stuff for two years, so it was a mistake we kept on making. But once again, this is all supposition, and we've been living in our heads for these past few days.
On my end, I'm not sure that what they're describing really would've mattered to me; I disliked the core gameplay enough to not make me want to plow ahead with the game anyway. And the inability to play by yourself effectively really made it tough for me to set aside time for it.