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.
In a manner similar to many of From Software's titles, particularly King's Field, the story of Shadow Tower Abyss is not a direct continuation to its predecessor; rather it keeps many of the themes and atmospheric elements, and functions as a new cycle of the first games plot.
The player assumes the role of an unnamed man with a military past, working as security for an archaeological dig deep within an unknown forest. Relics which prove the existence of highly advanced civilization and technology have been found, causing something of a sensation around what was first thought to be the remains of a simple tribe. Growing bored with the work, the protagonist wanders into the forest, and there encounters an old man who appears to be a local; the man claims to have knowledge of the greatest treasures of the ancient civilization, and leads the protagonist deeper into the forest. Eventually the two come upon the ruins of a strange, tall tower, wrapped in immense vines; the tower itself seeming to extend deep into the earth. Encouraged by the old man, the protagonist steps into an opening in the ruins of the tower, when suddenly a vine extends across the opening, sealing him in; outside the old man can be heard: "The hole is sealed. The offering is met."
With no way out the protagonist makes his way inside, and with no way back can only advance further into and up the tower in search of an exit (a classic dungeon crawler plot line, hearkening back to Eye of the Beholder). Through vague writings and dialogue from other characters, it is revealed that the Tower was once home to an ancient civilization, ruled by a divine king who gained untold power and prosperity for his people through the use of a mysterious artifact: referred to only as The Spear. An untold time before the game takes place, the civilization fell to ruin, corrupted by greed for immortality; the tower transformed into a treacherous labyrinth, and its denizens warped into cruel monstrosities.
Though the Tower seems man-made, it is in fact one massive organism, with sentience and a will of its own. Once making its home on another planet, the tower sustained the life of all living things, and in turn fed off the energy of those lives; some of the organisms made the Tower itself their home, the Tower itself acting as an ecosystem, connecting everything in it as one body.
Realizing one day that its planet was threatened by extinction from an unknown cause, the Tower regressed itself to a seed state, and launched itself into space, in search of another planet on which to perpetuate itself. Eventually its guidance systems died, and the planet drifted for untold years, until finally arriving at the planet on which the game is set.
Immediately the seed attempted to grow itself into the Tower it once was, but discovered that the light of the sun was ruinous to its body; the parts of the Tower that reached the surface immediately withered and died. With no options, the Tower contented itself to wait underground, doomed to die without being able to recreate the cycle of sustaining life and feeding on life.
As it was nearing the depletion of its energy reserve, the Tower felt a presence within itself, of a life form with greater intelligence than anything it had encountered before: primitive humans. Deciding that these were the beings it had been waiting for, the Tower captured the life forms and transformed them into parts of its new structure. However, the parts created from these life forms had minds of their own, and rebelled against the Tower; having no choice the Tower pruned these parts off and left them to die.
Again returning to its lengthy slumber, the Tower was at last awakened by a civilization of cultured human beings. Discovering the ancient remains of the Tower, the King of this civilization insisted on exploring the interior, despite the objections raised by his vassals and advisers. The Tower was pleased by the nature of the King, and these new forms of humans, because they were ambitious; and taking advantage of the King's wish for power, the Tower gave to him the "Lance". This Lance was imbued with the magic of the Tower, and allowed the King to expand and rule over territory without equal.
The only payment for the power being, the continuous sacrifice of humans, so that the Tower could continue its experiments on creating the perfect life-form.
In a few decades the King had built himself an unrivaled empire, the voice from the Lance guiding him at all times. But gradually the voice of the Lance began to diminish, until one day it fell silent. Though the King did not know, the experimental life forms the Tower had been creating all these years had run rampant, and usurped control of much of the Tower. Fearing that his power would be extinguished, the King decided to journey into the Tower and find the source of the troubles, leaving his people with one final command: "Until the day I return, do not stop the flow of sacrifices".
At the point where the game begins, and the main character enters the Tower, the place has fallen into chaos and decay; each floor of the Tower is made up of multiple self-contained areas, and whereas it used to be the case that all were governed by the one intelligence of the Tower, now they are controlled individually by the species that make them their home.
Each area is distinct in structure and environment, and in each the species within have adapted to suit the environment.
The Floors -
The Tower is made up of four floors, connected by a series of elevators.
Shrine of the Forest of the Depth (底森の祠): Technically not a part of the tower, but the overgrown remnants of the shrine constructed by the King to honor the Tower. The only entrance into the tower is hidden somewhere deep in this forest, protected by the disfigured remnants of the once-worshipers.
The Tranquil Shore (静澄の岸): An infinitely deep river runs through a cavern beneath the forest, flowing towards the Shadow Tower. A ferryman waits on the shore; his once ornately decorated craft carried the sacrifices meant for the Tower, but now the intricate carvings on its surface have faded and worn away, and the boat carries only lost travelers.
Level of Blue Light (蒼光の域): The bowels of the tower, and the first place a new entrant would see. Bathed in a perpetual green-blue light, the area contains devices which once created this light, as a means of energy for the Tower in place of sunlight - now only single device remains in operation. The creatures which once manipulated these devices are left without purpose, now that the Tower has ceased to function as it once did, and they roam the level aimlessly or continue to perform their duties without reason.
Level of Insects (奇虫の域): A massive hive suspended above the abyss. Filled with insect monsters who will vigorously defend the hive and their Queen, the Queen who has found a way to gain immortality through manipulation of the light energy of the Tower.
Level of Poison Inferno (烈毒の域): An area comprised of two floors: the bottom floor is steeped in pools of toxic waste, the upper clouded in a poisonous miasma. The area was once used as a disposal for waste produced in the Tower; the rotting carcasses and other contaminant waste dumped in the area are the reasons for the toxic atmosphere.
Level of Chalk (白亜の域): Carved entirely from the rock walls of the cavern, this area is quite human in its architecture. Once the home peaceful inhabitants, working under a benevolent ruler who allowed them access to the energies of the Tower. As the Tower was corrupted, the ruler went insane, and so too did the workers who relied on him for their sustenance.
Field of Spores (木賊の界: Populated by sentient plant life which has propagated itself through spores. The plants have a tendency to grow back unless their roots are totally destroyed.
Field of Water Falls (落滝の界): What was once a marvelous temple structure, now flooded after a section of the Tower caved in allowing water to flow inside. Populated with fish-like and reptilian amphibious creatures.
Floating Plateau (断崖の界): An area composed of narrow rock pathways and cave passages carved into the rock. Avian creatures, who pay no heed to the precarious footing, make this area their home.
The Red Sand Tower (赤砂の塔): Once upon a time the Tower was made up of numerous smaller towers, each extending skyward; now all that remains is this one, consumed by the ever flowing tide of red sand. The humans sacrificed to the Tower, experimented on and mutated, gravitated to this area and make it their home. The ancient King who entered the Tower ages ago still resides here, malformed beyond recognition.
Field of Deep Fog (濃霧の陣): Covered entirely in a deep fog, which is exhaled continuously by a strange creature in the center of the area. This area is responsible for the functions of all the rest of the Tower; the conscience of everything within the Tower gives off energy which is drawn to this place, and in turn energy is reciprocated back into the Tower.
Palace of Illusion (幻影の陣): The penultimate area of the tower before the apex chamber. It resembles a castle of human construction, but filled with various magical devices which impede progress. It is populated by worshipers of the Tower, who are unconcerned with the presence of others, and the powerful prototypes of the Tower's supreme being.
The game is played entirely in the first person with a minimal HUD, similar to both King's Field and the first Shadow Tower. Most strikingly different is that all melee combat is handled through the thumbstick: with left to right motions acting as a wide cleave, pushing the stick forward to stab, and pulling the stick back to perform an overhead attack. Even guns are fired by clicking in on the thumbstick, and feature no crosshairs.
Much of the difficulty of the game comes from the durability of equipment; everything other rings and necklace-like equipment can break, and often after only a few hits. Weapons will break after continuous usage which renders them completely unusable until repaired.
Repairing is accomplished one of two ways: using an item which restores the durability of every equipped item at the time of use (these can be found, very infrequently, or purchased from a limited supply), or through the repair stations placed throughout the tower. Using a repair station will demand a certain amount of hp to fix an item - the amount if hp depending on the quality of the thing being repaired (both the value of the item and the extent of the degradation).
Additional stations include a healing station, which demands the sacrifice of gear in order to order to heal HP and MP, a barter station which can also be used to store gear, and a save station - the only means of saving in the game.