Once, Sam Fisher was an agent of Third Echelon, assigned to infiltrate strongholds belonging to enemies of National Security, gather information and neutralize enemies if needed.

Times are changing, America's enemies are looking at new options, finding ways to make themselves more deadly. In order to star one step ahead of its target, Third Echelon is also changing and while Sam Fisher's foes are evolving and his allies are in flux, Fisher's own life will undergo some dramatic and permanent changes. And once that happens nothing will ever be the same.

With his life turned upside down, Fisher is on a new mission unlike any he has ever been sent on before. Where he used to penetrate defenses and gather information from the outside, now he is on the inside, working with those he has sworn to destroy and finding enemies among his allies. He is risking everything for the sake of the greater good, even if it costs him his identity or his life.

Play the game in a stealth manner or in a gun blazing way and your experience will be different every time you play. Try to sneak around the enemies and kill, interrogate or neutralize them without anyone else notice. There are 3 different endings depending on your choices in the game. Different settings will be visited during the game such as a prison, a boat in Cozumel, visit Africa, and many more.

You will get many different weapons and gadgets to help you through your journey. Use gadgets to close the lights, use gadget to electrify enemies in water pond, and scan the surroundings using your many visions (electric, night vision, heat vision) to identify potential gameplay objects around the worlds.

This version is quite different from the Xbox 360/Windows release. They share the same engine (although it is not multi-threaded), but this release adds an additional single-player mission with alternate ending, a new Spies vs. Spies online mode, 14 co-op missions playable offline (also online for the Xbox version), LAN, and 8 minutes of additional cinematics. There are also some changes in the storyline. The Wii/GameCube versions only have co-op multiplayer.

The Spies vs. Spies multiplayer offers different game modes:Team Hack*: similar to capture the flag, but you need to hack the opponent's computer and secure your own.

• Deathmatch: regular matches.

• Team Deathmatch: regular team matches.

• Key Run: similar to Team Hack, but with the addition of a key that needs to be obtained first to hack into the opponent's computer

• Sam Vs. All: a single player, Sam Fisher, has to sneakily hack into computers defended by an entire team.

• Countdown: similar to Deathmatch, with the addition of gameplay time provided by killing other players.