The game uses the same basic format as its predecessors, but it expands and tweaks the separate elements to near perfection. The single player mode and versus mode have been significantly improved and like Pandora Tomorrow, this game introduces a brand new play style. In Chaos Theory, you and a friend can test out your stealth skills against the computer in several customized cooperative missions.

The claim that single player Splinter Cell has been improved may come as a shock considering how excellent the original game was and how much of an improvement the sequel was. It begs the question, what could have possibly been improved? Well, here are the improvements as I see them.

Chief among the improvements are the additions to Sam's move list. This time out, his existing set of moves is complemented by some pretty down and dirty techniques.

Several of these have to do with his new razor sharp Rambo knife. You can use it to break locks instead of picking them (this makes a loud metallic sound that can alert enemies). You can use it to cut openings in material like tent fabric or hanging plastic covers like the ones painters use. But most exciting is your ability to use it on your enemies.

You can stab from behind or slice from the side, but what's most useful is the front attack. Anyone who has played either of the first two games understands the frustration of sneaking up on a guard and having them pull a crazy Ivan at the very last second. Well in Chaos Theory, it's not a problem. Just use the R trigger and Sam runs them through and cradles them right onto his shoulder so you can find a place to stash the corpse. The down side to this is lack of information. Kill everyone this way and you will miss out on valuable clues, obtained through interrogation, that help you complete the mission.

The quick attack concept doesn't end with the knife either, if you happen to be hanging above your mark, you can reach down and snap their neck with another quick tap of the R trigger. If you happen to be hanging from a balcony railing below them, pressing the A button will make you grab the creep and pull him over the edge and send him screaming to his death. And if that wasn't enough, on one level in Japan, you can actually punch through rice paper walls, grab guards and haul them back through. Once in your iron grip, you can interrogate him and end his miserable existence with a quick R trigger tap.

But don't fret if you are a pacifist, each lethal quick attack comes with a non-lethal version that you can perform by using the L trigger. When in front, he smacks them in the face with his palm or knees them in the stomach, while behind, he punches them in the side of the head or puts them in a sleeper hold. All look like they hurt but none leave a dirty spot on your conscience.

The other major improvements actually shine a not-so-pretty light on the previous versions of the game. The most obvious one is the ability to save anywhere. The notion of checkpoint saves was thrown right out the window; exactly where it should be. The choice of when and where to save should absolutely be left up to the individual. It's a feature of the game that allows you try different solutions to given problems and explore the game so much more. What better way to play a stealth game than to be able to try several different scenarios until you find one that lets you sneak past the guard or take him down without anyone knowing. It definitely helps in the parts of the game that have no obvious solution. In hindsight it was quite annoying at times having to restart a whole section just because of one tiny mistake.

Which leads into the last major single player improvement. No more three alarm system and no more single-detection-equals-mission-over garbage. The mission does get tougher when you sound the alarms, but it's not done in such an unrealistic fashion. Guards start patrolling and will actually not fall for some traps when alerted to intruders. You'll even hear them make comments like "who does this guy think he's dealing with, amateurs?" and "Oh no. That's a trap, I'm not going over there."

As in the previous games, when you set off an alarm, Lambert scolds you and warns you not to set off the alarms, but in this version when Sam prompts, "Let me guess, three alarms and the mission's over." The answer from Lambert is "No, of course not what do you think this is a video game?"

The tongue-in-cheek dialog doesn't stop there either. When interrogating enemies and chatting on the radio, you can hear hilarious references to Metal Gear Solid, Ghostbusters and even Harry Tuttle from the classic Terry Gilliam film Brazil. Each one represents the cherry on top of a superb new single player game.

Of course if you are Ubisoft Montreal, why stop there? You haven't even revamped the spy versus mercenary online mode or even invented any completely new game modes. Nowhere near a full days work for these guys. The changes to the spy versus mercenary mode cover the gamut. There are several new levels to choose from as well as five from the original: Museum, Warehouse, Deftech, Rivermall and Bank. Why they decided not to keep Cinema I'll never know, but it is gone nonetheless. While the old levels are definitely classics and welcome inclusions, the new levels are so much deeper it puts the originals to shame. Instead of selecting whether you will hack, steal or blow up the objectives. The new levels are designed where you can do all three on the same level. What's even better is that on some maps, some objectives have level altering side effects. Hacking an objective turns off laser alarms or blowing up an objective fills a particular room with steam that creates, in essence, a persistent smoke cloud. Other maps have objects you can interact with to knock down walls or drop boxes on unsuspecting enemies.

In addition to new maps, new gadgets have been included to add further depth to the versus mode. Spies can now use a thermoptic camouflage suit that gives them a Predator kind of invisibility that lasts for a few seconds then has to be fully recharged before using again. The also have a heartbeat monitor that lets you detect the heartbeats of enemies in distant zones in a manner similar to that of the laser microphone.

Mercenaries also have a few new devices at their disposal. They can customize their load outs with gas masks that protect them from toxic gas effects or a Camera Network Browsing Device (CNBD) that lets them see what the cameras on the level see. Finally, they can equip a backpack that either you or your teammate can use to refill your supplies of gadgets.

With all the new gadgets and the high level of interactivity of the maps, the game may be too new to know for a fact exactly how the balance will play out between the spies and the mercenaries, but it is an absolute blast figuring it out and learning how you can use the different aspects of the game to your advantage.

Like the single player mode, the developer made some improvements less related to game play and more related to the practicality of the game as a whole. For one example, it is no longer necessary to have at least one spy and one mercenary to start the match. This made showing a newbie friend the ropes impossible unless you had a third friend who would volunteer to run around as a mercenary. Another example knocked my socks off when I saw it because it is so incredibly necessary for a game of this depth. When you visit one of the maps, new or original, lighted arrows on the ground guide you as a spy to each of the objectives or interactive elements of the map. Lighted squares on the ground denote areas of interest. When you stand on these, text is displayed that explains what the area is for.

Finally, instead of fighting the insistent urges of the online community, they went and added an explicit death match mode where instead of customizing the number of lives and disabling the time limit to create the effect, you simply select it from a menu. In this mode you can't win by hacking objectives so you don't have to worry about non-death match spies screwing up your death match game by running straight to the objectives.

Since objective two has been thoroughly neutralized, we are left with only the cooperative mode, which is out of this world. The great part is that the coop mode has similarities to the single player mode and similarities to the versus mode, but really is an entirely different game in and of itself. The cooperative mode combines elements of coordination used by the spies in the versus mode with customized maps that have the look and feel of the single player missions. The result is the definition of fun. A split screen mode is available as well as an online one so you only need one copy of the game to experience the fun of cooperative play. It deserves to be stressed specifically that cooperative for Splinter Cell: Chaos Theory does not have the same definition as say a first person shooter in cooperative mode. You are not simply running around blasting enemies trying to compare scores at the end. This game requires coordination, communication and sometimes concentration.

Coordination comes into play because there are certain areas of the map that are inaccessible without it. The game mode provides special moves that are geared towards coordination like the ability to give your partner a leg-up boost to an area that by yourself would be unreachable. Another move lets you lower your partner by cable, Mission Impossible style, to reach areas of interest like computers or switches. Yet another ability lets one spy grab the shoulders of another and perform a backwards tumble that results in the other spy being hurtled in the appropriate direction.

Communication is essential obviously because you can't perform the coordination moves without it, but it has more subtle uses like communicating which rooms to sneak into and how to take down particular enemies. There is nothing cooler in a stealth game than you and a partner sneaking up on two CPU guards, listening to their conversation from the shadows, and then each grabbing one at the exact same second.

Concentration can be necessary depending on the goals you and your teammate set for yourselves when playing cooperative. Since it is possible to run in guns blazing in a Swat team capacity (low concentration) or sneak around the entire map using non-lethal attacks (higher concentration) your options are open. Either way, you are participating in a cooperative effort and simultaneously driving towards the same goal. The end result is something that will envelop even people that are not huge genre fans.

The culmination of these elements is what makes the cooperative mode of Splinter Cell: Chaos Theory such an exciting experience. And when you combine it with a vastly improved single player and a versus mode that takes the depth of interaction to a completely new level you have a truly extraordinary example of what a video game should be. The only question I still have is, if Ubisoft continues this revolutionary trend of development, what could possibly be in store for the next generation console systems. At this point, I can't even imagine what the future will hold. One thing is absolutely certain, and that is Splinter Cell: Chaos Theory is one of the best games I have ever played.