Metal Gear Solid 2: Substance

Metal Gear Solid 2 carries the subtitle of "Tactical Espionage Action," and most of the game involves the protagonist sneaking around to avoid being seen by the enemies. Most fundamental is the broader range of skills offered to the player. The first-person aiming mode allows players to target specific points in the game, greatly expanding tactical options; guards can be blinded by steam, distracted by a flying piece of fruit or hit in weak spots. Players can walk slowly, allowing them to sneak over noisy flooring without making a sound, or hang off walkways to slip past below guards' feet.

The corner-press move from Metal Gear Solid, which allowed players a sneak peek around the next bend, is expanded to allow players to fire from cover. Other abilities included leaping over and hanging off of railings, opening and hiding in storage lockers, and sneaking up behind enemies to hold them at gunpoint for items and ammunition. Players can shoot out the enemy's radio, so they are unable to communicate with others on their team. The environment also has a more significant impact on the stealth gameplay, taking into account factors such as weather, smell, atmosphere, and temperature.

Sons of Liberty takes place within an alternate history of events, in which the Cold War ended during the late 1990s. The game's story focuses on two narratives that occur around and near New York City – the first in 2007, two years after the events of Metal Gear Solid; and the second in 2009. The game's plot is the fourth chapter of an overarching plot concerning the character of Solid Snake.

The main protagonist of Metal Gear Solid 2 is a young rookie agent named Raiden. He is supported by his commanding officer, the Colonel, and Rosemary, his girlfriend. Allies formed on the mission include Lt. Junior Grade Iroquois Pliskin, a Navy SEAL of mysterious background who provides his knowledge of the facility; Peter Stillman, an NYPD bomb-disposal expert; Otacon, a computer security specialist and friend of Solid Snake; and a cyborg ninja imitating Gray Fox's persona, first calling itself Deepthroat, then changing its name to Mr. X.

The creator Hideo Kojima's original design document for the game was completed in January 1999. The Japanese document was published by Konami in 2002, and translated into English in 2006. It mentioned that the game was originally going to be called Metal Gear Solid III to symbolize Manhattan's three tallest skyscrapers. The document outlines new game mechanics and features, such as bodies that need to be hidden, enemies being able to detect shadows, lights in an area that can be destroyed to affect enemy vision, realistic enemy AI that relies on squad tactics rather than working individually, and multi-level environments that add an element of "vertical tension" to the stealth gameplay.

It also outlines themes, such as passing on memories, environmental issues, and particularly social themes regarding the "digitization of the military", digital simulations, the "digitization of operational planning", the "digitization of everyday life", and the "effects of digitization on personality". The document stated that the "aim of the story" involves "a series of betrayals and sudden reversals, to the point where the player is unable to tell fact from fiction" (departing from the "very clear and understandable story" of its predecessor), that "every character lies to (betrays) someone once", blurring the line between "what is real, and what is fantasy", and "ironies aimed at the digital society and gaming culture".

Metal Gear Solid 2 received "universal acclaim" according to review aggregator website Metacritic, where it is one of the highest-rated games on the website, and remains the highest-rated exclusive on the PlayStation 2. Game Informer gave the game a score of 10/10, while GameSpot gave the game a 9.6 rating, stating, "It boils down to this: You must play Metal Gear Solid 2." Critics praised the title's stealth gameplay and the improvements over its predecessor, as well as the game's level of graphical detail, particularly in the use of in-game graphics to render plot-driving cutscenes.

The title's storyline, however, was initially divisive and became the source of controversy. Hideo Kojima's ambitious script received praise for exploring numerous social, philosophical, and cyberpunk themes in significant detail, and it has often been called the first example of a postmodern video game. However, some critics considered the plot to be "incomprehensible" and overly cumbersome for an action game, and also felt that the lengthy dialogue sections heavily disrupted the gameplay and that the dialogue itself was overly disjointed and convoluted. The surprise introduction of Raiden as the protagonist for the majority of the game (replacing long-time series protagonist Solid Snake) was also controversial with fans of Metal Gear Solid.

Since its launch, Metal Gear Solid 2 has been widely regarded as one of the best and most influential video games of all time. In a 2006 viewer poll conducted by Japan's Famitsu magazine of top 100 games of all time, Metal Gear Solid 2 was ranked at No. 42 in the poll. In the 200th issue of Game Informer Magazine in 2009, its list of top 200 games of all time ranked the game at No.

50 on the list. Metal Gear Solid 2 was ranked No. 7 in Game Informer's 2008 list of the top ten video game openings. In 2010, GamesRadar included the game in its list of top seven games "with mega plot twists you never saw coming".