Splinter Cell: Chaos Theory is one of those few games you'll look back on in years and think, "Wow, that was fun" and then return to play it over and over again.
If you are a veteran of the SC games, you'll feel immediately at home with the controls. You will have some minor gameplay tweaks however that make this a much more accessible, yet tough game. You have two types of attacks now, lethal and non-lethal. Pulling the left trigger while near a guard will deliver a palm strike to the guard, knocking him out cold. If you aren't a pacifist however and choose to bring death to all you cross paths with, pulling the right trigger makes the hero of the game, Sam Fisher, pull out his shiny new knife and, depending on how you are facing the enemy, stab him in the kidney or slash his throat. Ouch....
The graphics are jaw dropping on all three consoles, but the PC and Xbox versions shine the brightest. Remember when the first Splinter Cell came out and the world was in awe of its lifelike visuals then? Well, three years later, the first game looks very inferior to the behemoth Chaos Theory. Rain droplets bounce off of your character while outdoors. Your character gets a "wet" look while outdoors with small things like a sleek suit, wet hair, and so on. Lights and shadows are much more realistic now in Chaos Theory and vastly vary from level to level. In one level, you'll be traveling through the back alleys of New York City while in other levels, you'll be sneaking through Japanese houses. All of the levels are humongous, with various ways of getting from point A to point B.
The sound is incredible. There is a new gameplay addition to this version -- the sound meter. You can use ambient noise to your advantage and move along with the sound, letting it mask the sound of your movements. During your game as Sam Fisher, you'll travel through apartment complexes with boomboxes blasting, bustling crew quarters on a freight ship, battlefront sounds, and so on. The soundtrack is very moody. During times when you are sneaking, it is nice and slow paced. During times when you are discovered by the enemy however, the music rapidly picks up as you run from your enemies, usually in a hail of bullet fire.
A new mode placed in the game is a two-player co-op mode for offline AND online play. This has a plot somewhat tied in with the main story's plot where you take the role of two brand new Splinter Cell agents on their first missions. The gameplay is similar to the single player game, but you have new two-player moves you can do, like tosses for example. Teamwork is a big deal in this mode, and if you aren't careful, you'll wind up dead. An incredible addition to the already incredible game.
The online mode from the previous installment, Pandora Tomorrow, returns with new tweaks and maps for people to link up Xboxes over Xbox Live or connecting Xboxes together for a LAN party. I myself haven't gotten to try this mode, but I have heard many good things about it. So if you have XBL, by all means, check it out.
Overall, if you are a fan of the Splinter Cell games, stealth games, or even remotely interested in this title, go out and get it. You won't regret it.