Shadows of Brimstone: Forbidden Fortress can be played on its own as a stand-alone game, or it can be used in combination with any and all of the other Shadows of Brimstone products already available! It is fully compatible, in every way! For new players, Forbidden Fortress will make a great introduction to the world of Shadows of Brimstone, and for veteran players, it adds a ton of new content, including two brand new Worlds to explore - the Japanese castles and temples of the Forbidden Fortress and a living world inside a massive creature in the Belly of the Beast. It also includes a brand new set of Heroes and Enemies to add to your games. With the option of starting your Heroes in Feudal Japan or the Old West, or having a mixed party of Heroes, drawn from both worlds, the possibilities are endless!