I'm glad you brought this up! Imo, Melvor Idle is a PBBG because persistence doesn't necessarily have to be external.
Multiplayer has been kind of hit or miss, some people are adamant that it is required, other's aren't.
For the last jam we had Cooperation as one of the criteria but there wasn't enough time to bring it in so everybody scored really low on it. So maybe we can just ignore that portion in favor of time?