Rather than asking for twitch reflexes and an emphasis on mass murder, Splinter Cell: Chaos Theory asks the player to be aware
This is not a game where the locales are merely canvases to spill blood - every inch of ever level is laden with multiple ways to progress through the mission. Shadows, vents, windows, pipes and balconies which can be hung off of... not only are you given a wide array of ways to avoid enemy detection, but these assets can be used to silently (and stylishly) take out enemies.
Not only does the environment give an incredible amount of replay-friendly playstyle options, but it also reeks of atmosphere and immersion in a way that I've never seen in a video game since. Not only are the dark, glistening graphics and ambient sounds well-done, but the moody soundtrack by Amon Tobin serves as the syrupy glaze to the atmospheric pancake. Meanwhile, the level design has a realistic feel to it, as though every hallway that you enter could be a real place.
Overall, Splinter Cell: Chaos Theory is a gameplay masterpeice and a technical marvel that still impresses today, over ten years after its release. Almost every aspect has such a great level of polish that, despite the game's relatively niche genre, I reccomend this game to everyone who has ever picked up a game controller.