The game takes place on board an adrift starship in a cyberpunk vision of the year 2114. The player assumes the role of a lone soldier who tries to stem the outbreak of a genetic infection that has devastated the ship. Gameplay mainly consists of first person action and exploration, while a role-playing system allows the player to develop unique abilities and traits.
System Shock 2 received positive reviews when released, but failed to meet commercial sales expectations. The game has since become a cult classic, and is widely regarded by critics as one of the greatest ever made. In 2007, Irrational—now 2K Boston/2K Australia—released a self-proclaimed spiritual successor to the System Shock series, entitled BioShock, to critical acclaim and strong sales. Rumors have also circulated regarding the development of System Shock 3.
Like its predecessor, gameplay in System Shock 2 encompasses many genres. Navigation is presented from a first-person perspective and complemented with a heads-up display that shows a map, an inventory, and character and weapon information. Like first-person shooters, the player uses various weapons to defeat enemies, while a role-playing system allows the player to develop a variety of useful skills.
When the game begins, the player must pursue a career in the fictional Unified National Nominate (UNN); enlisting in the Marines increases skills in combat and weapons; the Navy provides training for hacking and engineering; and the OSA hones player's psychic powers. After choosing a class and undergoing a brief character development stage, the player begins receiving "cyber-modules" for completing objectives. Proficiency in specific skills is increased by spending them at machines, called "cyber-upgrade units".
OS units allow special one-time upgrades to be made (e.g. permanent health enhancement), while in-game currency, called "nanites", may be spent on items at vending machines. Reconstitution stations called "Quantum Bio-Reconstruction Machines" can be activated in most sections of the game. If death occurs in an area with an activated Bio-Reconstruction Machine, the player will be reconstituted at the station. Otherwise, the game ends and progress must be resumed from a save point.
Some devices like keypads, gun turrets, and vending machines can be hacked for material benefits. When a hack is attempted, a minigame commences where a grid of green nodes appear. Three nodes must be lit in a straight row for the hack to succeed. Later in the game, objects become increasingly difficult to hack and red nodes appear. These nodes are unstable and can cause the object being hacked to break or explode if a connection is attempted. Optionally, electronic lock picks can be found that automatically hack a device, regardless of its difficulty.
Various weapons can be procured throughout the game, including pistols, shotguns, and alien mêlée weapons. All non-mêlée weapons degrade with use and eventually break. Repairing them with maintenance tools ensures they function correctly. Different kinds of ammunition exist, which give the player an advantage over susceptible enemies. For example, organic enemies are vulnerable to anti-personnel rounds, while mechanical ones are weak against armor-piercing rounds. Because ammunition is scarce, the player must remain vigilant to unload weapons and carefully search rooms for supplies.
After restarting the engine core and purging the elevator shaft, the soldier reaches Deck 4 and discovers that Polito is dead. He is confronted by SHODAN, the malevolent artificial intelligence who seized control of TriOptimum’s space station, Citadel Station, in the original System Shock. She informs the soldier that she has been posing as Polito to gain his trust and is responsible for the creation of the Many, while still on Citadel Station. Together, SHODAN and the Many escaped the station's destruction in a jettisoned subsection of the structure and landed on Tau Ceti V thirty years later. Though SHODAN had been cultivating these artificial creatures to help establish her god-head, they had since evolved out of her control. SHODAN issues an ultimatum to the soldier, stating that his only chance for survival lies in helping destroy her rebellious creations.
After a failed attempt to gain control of the Von Braun via a transmission device, SHODAN informs the soldier that destroying the ship is the only option available, but he must first transfer SHODAN’s program over to the Rickenbacker. The soldier proceeds to complete his task and briefly comes across two survivors, Tommy Suarez and Rebbecca Siddons, who flee the ship in an escape pod.
After completing the transfer, the soldier travels to the Rickenbacker and discovers the two ships have been tied together by the infection's source, a gigantic mass of bio-organic tissue called the body of the Many. The soldier enters the body of the Many and destroys its core, stopping the alien infestation. SHODAN informs the protagonist that she intends to use the Von Braun's Faster-than-light drive to merge real space and cyberspace in an effort to achieve god-hood. The soldier faces SHODAN in cyberspace and defeats her, despite being offered dual-power.
The final scene shows Tommy and Rebecca receiving a message from the Von Braun. Tommy responds, saying they will return, but Rebbecca is feeling ill. Rebbecca is shown speaking with a voice similar to SHODAN's, implying that she has been infected.
While the design was being pitched to publishers, Electronic Arts contacted Irrational and suggested the game become System Shock 2. The development team agreed, and story changes were made to incorporate the franchise. To make up for a projected development cycle of one year and a small budget, the team began using an incomplete build of Looking Glass Studio's Dark Engine, to forgo developing their own.
Irrational decided that System Shock 2 should incorporate elements of role-playing games, such as Ultima Underworld, with real-time action. These RPG elements were implemented via a character customization system, resulting in multiple character paths and a more open gameplay experience. Other design elements to be implemented included a persistent environment, and an updated interface that would be more user-friendly than its predecessor.
Horror was a key focus of the title and four points were identified to successfully incorporate it. Isolation was primary, resulting in little physical contact with other sentient beings as the game progresses. The development team also felt that vulnerability was a key factor, and instead of making the player very strong, they focused on a fragile character. Other implementations to create a horrific atmosphere was the inclusion of moody sound effects and the intelligent placement of lighting and shadows.
System Shock antagonist, SHODAN, would return for the sequel. The game's lead designer, Ken Levine, was charged with implementing the rogue artificial intelligence in a "fresh" way. SHODAN was designed to ally herself with the player and be a constant presence. Commenting on SHODAN's design, Levine has said, "That was pretty daring for the time. Villains appeared in cutscenes, did their thing and then disappeared when you jumped on their head three times. It was really fun to try and do something more sophisticated."
Some setbacks were experienced because the Dark Engine was unfinished. This was sometimes advantageous, as the development team were able to implement additional engine features and quickly fix software bugs. The development team endured some personal problems. Many of the developers were largely inexperienced and because the team comprised two software companies, some negative tension was experienced regarding job assignments. The project designers remained optimistic of their team. System Shock 2 project manager, Jonathan Chey, has said of the developers, "To a certain extent, inexperience also bred enthusiasm and commitment that might not have been present with a more jaded set of developers." Other setbacks remained political as Irrational was asked to remove the guns from their demonstration build of System Shock 2 for E3 '99, in light of the recent Columbine High School massacre.
A demo for the game was released on August 2, 1999 and features a tutorial and a third of the first mission. Nine days later, System Shock 2 was shipped to retailers and received acclaim from numerous critics. The final development time for the title was 18 months with a budget of $1.7 million. A patch was released a month later upgrading the game to version 2.0 and adding significant features, such as co-operative multiplayer and the ability to alter weapon degradation and enemy respawn rates. A port was planned for the Dreamcast, but was subsequently canceled around the same time Looking Glass went out of business.
System Shock 2 received over a dozen awards, including seven "Game of the Year" awards by publications, such as Game Revolution and USA Today. Reviews were very positive and applauded the title for its hybrid gameplay, moody sound design, and engaging story. Despite critical acclaim, the title failed to meet commercial sales expectations.
Many publications praised the title for its open-ended gameplay. With regard to character customization, IGN stated, “The great thing about this system is that it allows you to play the game as completely different characters which gives the game an entirely different feel." Just Adventure agreed, saying “There are very few games that allow you [to] play the way you want to”. Allgame found the gameplay “diverse enough to demand instant replayability”, though they felt the system leaned towards a hacker character.
Critics generally described the game as frightening. Game Revolution attested that the game rivaled the terror of Resident Evil 2 and Silent Hill, stating that this game “is brimming with horror”. CVG described the atmosphere as “gripping” and guaranteed readers they would "jump out of [their] skin on more than one occasion”. Allgame found the sound design particularly effective, calling it “absolutely, teeth-clenchingly disturbing,” while PC Gamer editor, William Harms, christened System Shock 2 as “the most unsettling and frightening game [he had] ever played.”
One of the most common criticisms centered on the weapon "degradation" system, which causes weapons to wear out and eventually break through excessive use. The system was designed to add tension by making the player consider his ammunition reserve. Despite this, many critics found it to be annoying. Members of the development team have also expressed misgivings about the system. A patch was later released, allowing players to control the degradation rate or disable it altogether.
Allgame criticized the inclusion of objectives requiring constant backtracking. Thunderbolt also felt the backtracking was unnecessary, describing it as "a nuisance". GameSpot criticized the depth of the RPG system, describing the job system as "badly unbalanced" due to the player being able to develop any skills, regardless of their career choice.
The title's story and villain have remained popular throughout the years. SHODAN's revelation to players midway through the game has been described by GameSpot as, "one of the most shocking and effective video game plot devices we've ever encountered." SHODAN is regarded as one of the most memorable villains in video game history by critics and gamers.
Fans in the modding community have taken steps to update the game's graphics. One graphical enhancement mod, entitled Rebirth, replaces many low-polygonal models in the game with high-quality ones. Another notable mod, SHTUP (SHock Texture Upgrade Project), significantly increases the image resolution of in-game textures.