The Dark Tower
The Dark Tower RPG is a complete game that uses a modified version of Chaosium's Basic Roleplay system (the system used for Call of Cthulhu).
The Stephen King universe lends itself to world-hopping scenarios; thus, characters from different realities can encounter each other. Players can originate in many realities, including worlds very similar to our own modern day, as well as other realities like Mid-World (the world of the Dark Tower series).
The collection includes rules on character creation, a book of 60+ inhuman creatures, two books detailing magic and psychic abilities, and a collection of character templates.
It can be downloaded here.
A map of Mid-World can be downloaded here. Newfags won't get this.
