I've been on a DC Animated Universe kick and wanted to revisit these. It's a really good game, but it does have a weaker back third. It's a good thing it's a joy to fight and explore because I really dislike this game's take on the series. It's ugly and mean and cynical without coming close to the best ugly, mean, and cynical Batman stories. It just sort of presents one note to you at all times: that every member of the rogue's gallery is the most sick and twisted monster you could possibly imagine.

I think this one's in the conversation for greatest games of all time. Certainly one of the best of its generation. It's remarkable what a leap there is between the first game and this one over so little time, especially considering the original already felt like it was from the future in 2002.
The first two games are essentially obstacle courses. I feel like this often gets leveled at them as a criticism, but I don't think that's a bad thing by any means--that's more or less what all stealth games are when you get down to it. What sets Chaos Theory apart is how it takes that trial and error obstacle course design and applies it to maps that are far more complicated and intertwined than anything in the first two games. There are multi-tiered buildings full of vents, pipes, and security doors providing many different paths to your goals. The game also has sub-objectives (a bit like Goldeneye's) that reward you for exploring every inch of the map. Guards are predictable and easy to manipulate--a positive. They'll also provide information about the map to you if you grab them. Nearly everything you can do winds back around into your main or bonus objectives. It's immensely rewarding.
This is also one of the Coolest games ever made. It looked unbelievable in 2005 and thanks to its meticulous lighting direction it still impresses. Only the character models remind you that this is an Unreal 2.5 game from 20 years ago. The locations you visit are hugely varied (cargo ship! Bank heist!) and I can't applaud Amon Tobin's score enough. You should get spotted in every level just to hear how the music evolves.
Some stray notes:

-There's like maybe one bad level out of the lot (Seoul 2), plus a "boss" encounter at the end of one otherwise good level that kind of blows.

-The plot is nonsense but it's better nonsense than Pandora Tomorrow. It at least feels like a proper Clancy spy thriller again, not an extended joke about airport security. They finally settle on the best version of Sam here, too--I love his cranky middle aged American banter.

-Speaking of, in general this game is really funny, minus some tiresome accent humor in some levels. Grabbing a guard nets you an instant manzai routine between Sam and his foe. He's funny without being irritating, and his politics make sense again. Remember how in Pandora Tomorrow he kept making surprisingly lefty asides? I sort of doubt Sam Fisher is anything left of Reaganite.

-Again, the score is amazing. It's one of my favorite game soundtracks of all time. If you've never heard it before, listen to it. It's one of Amon Tobin's best albums, in my opinion. I'm so sad that the bank heist music never made it onto the official album release, though...

-This game feels like an immersive sim just for different kinds of stealth builds.

GOATed game, I need stealth to make a comeback.