Hi! Sorry for the delayed response. I designed this with a GM and 2-4 players in mind. Three is probably the sweet spot.
I'm not sure about solo play. It's probably not conducive to solo play since the players' experience depends on going into the adventure completely blind, including information about the genre and their own PCs.
That said, I could probably create a solo version if there was interest.
I hope this helps. I hope you enjoy the game!
TS