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