Shadows of Brimstone is a fast-pasted, cooperative, dungeon-crawl boardgame set in the Old West, and mixed with Unspeakable Horror! Each player creates a character, taking on the role of a classic Western Hero Archetype, such as a Bandido, U.S. Marshal, Gunslinger, or Saloon Girl. Forming a posse of Heroes, the players take their characters down into the mines in the foothills surrounding the demonically overrun town of Brimstone. The Heroes can embark on a variety of different missions, from finding and sealing a gateway to another world, to rescuing a farmer's son who was hauled off in the night by a horrible creature. The Heroes explore a dynamically generated mine, overcoming dangerous encounters and fighting savage creatures, while collecting up useful Gear and ancient Artifacts to help them during their adventures. Heroes can even find portals to other worlds, stepping through to continue their adventure on the other side.