Shadow Tower Abyss was developed by From Software, as a tangentially related sequel to Shadow Tower. It is a first-person dungeon crawler in the tradition of Ultima Underworld; with the player moving linearly from one level of the tower to the next, but with each level being open to exploration. Though taking place in a largely dark fantasy setting, the game includes modern weaponry and equipment, such as assault rifles and gas-masks. The game operates on a punishing cyclical economy, in which the player sacrifices health to repair their equipment, and equipment in turn is sacrificed to heal the player; traditional money can be found and used to purchase healing items, but it is extremely sparse, giving the game a survival horror-esque quality.
Shadow Tower Abyss was slated for a North American release, but was canceled by Sony due to poor reception of the first Shadow Tower game.