I just watched Ladyhawke for the first time. Yes, I know I'm late to the party. However, it gave me a great idea for collaborative solo play in TTRPGs.
Many of us play solo TTRPGs because we can't align schedules with others. What if we didn't have to? What if the lack of alignment was built right into the gameplay loop?
In Ladyhawke, Navarre and Isabeau are two lovers who are cursed. Navarre lives in human form by day and turns into a black wolf at night. Isabeau lives as a human at night but becomes a hawk during the day.
Dr Jekyll lives as a scientist, occasionally losing control or taking a drug to pass off control to Mr Hyde.
Bruce Banner is a brilliant scientist who turns into the Hulk when he gets angry.
You get the idea. There are a lot of similar stories. So, how does this affect gameplay?
You could recollect the other player's adventure if you inhabit the same body. If you're two separate characters, like in Ladyhawke, then perhaps you communicate through other means, like a 3rd party NPC or journal. In this way, I could play a day or two, journal what happened and any key events, and pass it on to you to take over. This would even introduce interesting dilemmas for play, where we may be mid-quest when the hand-off takes place, but our characters have different skills. Or you met a key NPC, but they don't know who I am and are afraid of me.
If you choose to play in this solo-but-co-op mode, set some ground rules in your session 0 by answering the following:
This style of play is missing from a lot of TTRPGs. There are games where you essentially have a penpal-type system, but nothing integrates it right into the game's mechanics. How else can we let our real-world context bleed into the game meaningfully?