There is a Xbox 360, PC, and the PlayStation 3 version that can be reached here.
Created by Splinter Cell and Chaos Theory developer Ubisoft Montreal, this (as then) last-generation version of Splinter Cell: Double Agent was developed for the Xbox, PS2, Gamecube and Wii. Opposed to it's counterpart it focuses purely on light and shadow based stealth and reuses many assets from it's predecessor Chaos Theory.
Although both versions conceptually feature several of the same missions and locales, as well as their own individual ones, the level and art design are drastically different from each other.
The online gamemode from past iterations isn't present in this version, and is substituted by a four mission co-op campaign and six player Spies vs. Spies multiplayer.
The story of Double Agent revolves around Sam Fisher's breakdown after the death of his daughter. Faced with this hardship, Sam takes up an assignment to infiltrate an American-based terrorist group known as the JBA.
Much of the game's story is told in past-tense by the means of a phone call taking place between Fisher and Assistant Director Williams, an NSA executive hired to watch over Lambert and Third Echelon in an effort to keep things in line. These conversations play before or after missions, over a rudimentary collection of images and video. These scenes can vary slightly depending on particular actions taken in the game, and occasionally coincide with other pre-rendered cutscenes, several of which are featured in both games.
One ending exists in this version of Double Agent. Although the result of both games is Sam Fisher being on the run from the NSA, leading into Splinter Cell: Conviction, the events immediately prior play out entirely different from each other.
Gameplay in Double Agent is very similar to former titles, with the addition of a trust system gauging relationships between the JBA and NSA. This results in a need to balance trust between the two groups by performing optional objectives or making decisions in favor of one alignment. The standing on the trust meter also influences the equipment received for each mission.
At two intervals in the game, Sam is tasked with objectives inside of the JBA compound; unlike the higher-gen version, these missions are not timed, and instead feature a balaclava-clad Sam Fisher operating around the headquarters in the cover of night. In these segments Sam is equipped with a compact launcher, which uses non-lethal ammunition like rubber bullets and tranquilizers, alongside the more standard gadgets. Here JBA members can be interrogated, and can make an effort to apprehend Sam if discovered, resulting in a QTE.