solo rpg solo play solo game master guide combat emulator theme story conflict strategy roleplay writing mythic dungeon crawl toolbox summary hex-crawl demo oracle solo gm list video rules cheat sheet pdf obstacle free module ian irvine freeform association text-based 2d6 dungeon improvisation mechanics inspiration problem solving exercise review motivation play gameplay imagination cheat adventure podcast shadow dark scene choose your own adventure role play killing your darlings beginner cthulhu gwydion solo-play paid song list plot twist d&d drivethrurpg wisdom tiles theater of mind published listen solo gameplay module solodark tweaks cinematography