I'd played solitaire TTRPGs before, and have been trying to get myself to do it again for a while now. There are a few I've heard of, but not a lot I've actually played.
Four Against Darkness looked neat. I'd peeked at it once, and it seems a bit more old-school D&D in some ways. It's a fleshed out system where you randomly build a dungeon encounter with character types suited for the format.
Dungeons and its expansion,
Dragon Fang Mountains, uses a dice pool system and is a bit more streamlined. It's more events-based than making a whole map. I have never beaten any runs of this game.
There's always
Tunnels and Trolls for classic games, which has a few CYOA-style modules floating around. There's a free demo version of the basic rules I've linked.
I know r/Solo_Roleplaying really seems to treat
Ironsworn as its sacred cow. Never played. It's based in Powered By The Apocalypse rules, and seems to be a vikings-esque dark fantasy game from afar? I can appreciate a Dark Souls and a SKALD for dark fantasy video games, but viking stuff is overrated IMO.
Of course, there's also something called
Scarlet Heroes. This allows you to play old-school D&D-esque games solo. There's a new funky damage dice rule, something called a Fray Die to damage enemies, and a way to reroll when you'd be defeated by some adventure-ending spells and effects (save-or-die poisons, sleep spells, petrification, et cetera). It has this Southeast Asian theme, more Chinese than anything, but I recommend this quickstart version the most of any of these from personal experience.
Aaaaand, of course, there's also just BSing your favorite game systems in ways to play them solo. Using simple oracles for randomization, dungeon generators, et cetera. I usually prefer simpler RPGs to run solitaire, but I've been dying to do it with Savage Worlds. One of my favorite oracles for generating plot twists is
Impetus. As for when to ask a question to determine in-world answers? A simple roll of a six-sided die, meaning...
- No, and...
- No
- No, but...
- Yes, but...
- Yes
- Yes, and...
Good luck and happy gaming!