Plot and Themes
The first game explains that "Splinter Cell" refers to an elite recon-type unit of single covert operatives (such as Sam Fisher) who are supported in the field by a high-tech remote team.
In the first three games (Splinter Cell, Pandora Tomorrow, Chaos Theory), terrorists are planning attacks, usually by use of information warfare, which Sam Fisher, an operative for Third Echelon, a secret branch of the NSA, must prevent. The missions range from gathering intelligence to capturing and/or eliminating terrorists.
In the fourth game, Double Agent, Fisher assumes the identity of a wanted criminal in order to infiltrate a terrorist ring.
The fifth game, Conviction, starts after events in the conclusion of Double Agent: Sam has abandoned Third Echelon. When he discovers that the death of his daughter Sarah had not been an accident (as had been purported at the beginning of Double Agent), he strikes out on his own in search of those responsible.
Trifocal Goggles
A device used for seeing in the dark features strongly in the series. Originally, Tom Clancy had rejected the idea of Sam Fisher having these "trifocal goggles", having stated that such goggles (with both thermal vision and night vision) were impossible to make. The creators argued that having two separate sets of goggles would have made for awkward gameplay and convinced Clancy to allow it. This also gave the Splinter Cell series a recognizable signature, a desirable feature. Current technology allows goggles with both thermal and night visions (as used in Tom Clancy's Rainbow Six: Vegas games) to be available for the military, although the goggles featured in the games are still much more compact than their real-life counterparts.
Characters
The characters of the games, as well as the organization "Third Echelon", were created by JT Petty. The main recurring ones are:
Sam Fisher is the main protagonist of the series. The character ranks 24th on the "Guinness Top 50 Video Game Characters of All Time" list.
Irving Lambert, leader of "Third Echelon", serves as the player's guide by leading Fisher through the games' missions, until he is killed as part of Double Agent's story.
Anna Grimsdóttír is portrayed as an official Third Echelon hacker and analyst, who helps Fisher when technical obstacles need to be overcome. In Conviction she takes over the role of guide from the deceased Lambert; her character also becomes the source of dramatic tension in the story.
Gameplay
The encouraged way to progress through the games is to remain hidden, select non-obvious routes, and utilize diversions to pass guards. The first game in the series only features a single-player mode, Pandora Tomorrow introduces a two-on-two multiplayer mode. Chaos Theory further develops that mode and introduces a cooperative mode. Cooperative mode plays similarly to the single player mode, but adds situations that can only be overcome as a team. The cooperative storylines in Chaos Theory and the sixth generation version of Double Agent parallel those of Sam's actions in the single-player modes, letting players act on information he obtained or provide support in the field.
Double Agent introduces a morality factor: Fisher may now encounter conflicting objectives between his superiors and the terrorists. For example, the terrorists may assign a mission to assassinate someone, while the NSA simultaneously instructs the player to prevent the assassination. This creates a delicate balancing act between gaining the trust of the terrorists and fulfilling the mission assignments. In addition, Fisher must not do anything to reveal to the terrorists that he is a double agent (such as let himself be seen with an NSA gadget), otherwise he will lose instantly.
Conviction utilizes a much faster and more violent[original research?] form of stealth action gameplay than previous games in the series. It retains the cooperative multiplayer mode of the two preceding games.
