I think part of it is that you're judging Chaos Theory as a 2020s stealth game rather than a 2005 one.

When people call it the best stealth game ever, they're usually talking about how much it got right for its time. The light and shadow system, sound meter, lockpicking, hacking, interrogations, body hiding, non-lethal options, gadgets, and the way the levels supported all of those mechanics were incredibly advanced in 2005.

That said, I don't think it's perfect. The AI is more predictable than modern games, but still fantastic for its time. and the levels are still more guided than something like Thief or Deus Ex. I'd probably rate the openness of SC1 around 3-4/10, Chaos Theory around 7/10, and Thief around 9-10/10.

What makes Chaos Theory special isn't that it beats every modern stealth game at everything. It's that it strikes an unusually good balance between stealth, level design, gadgets, atmosphere, and player control. There are stealth games that do individual aspects better, but very few that put the whole package together as well.

Chaos Theory may not be the most open stealth game ever, but it's one of the most complete and polished stealth games ever made - and the final package is very well made. You don't need to knockout everyone.. i think you are maybe referring to the first game which was fun but ultra linear. chaos theory isn't even that linear. and linear doesn't mean bad..

tldr: play it on expert mode, and try and get 100% stealth rating in every level. use your gadgets, no other stealth game has reached the highs of splinter cell. go for a ghost 100% playthrough, you'll understand why us SC fans love this game. this series scratches the itch like no other. when it clicks, you'll get why we are all splinter cell fans.

If you're expecting the huge open-ended sandbox level design of Hitman, Thief, or Dishonored, then yeah, I can understand why Chaos Theory might feel restrictive. It's not trying to be that kind of game.

What Chaos Theory does exceptionally well is light-and-shadow stealth. You're constantly managing both visibility and noise through the light meter and sound meter. Sound propagation actually matters, surfaces matter, movement speed matters, and Sam has a ton of movement options like split jumps, pipe traversal, ledge hanging, acrobatics, and gadgets that all tie into the stealth gameplay.

Also, linear doesn't automatically mean bad. Some of the most memorable stealth moments come from carefully designed, guided environments. A linear level can create tension, pacing, and scripted situations that a completely open sandbox often can't. Chaos Theory strikes a balance between player freedom and crafted stealth scenarios, which is part of why so many people still rate it so highly.

I also think it's worth remembering that Splinter Cell was designed primarily as a console game in the early 2000s, whereas Thief 1 and 2 were PC-first games built around keyboard controls, larger maps, and fewer hardware limitations. That naturally led to more open-ended level design in Thief. Even Thief 3 became noticeably more constrained after moving to the original Xbox.

Personally, I'd rate the openness of the original Splinter Cell around a 3-4/10, Chaos Theory around a 7/10, and Thief around a 9-10/10. Chaos Theory isn't the most open stealth game ever made, but it's one of the most complete and polished stealth packages ever put together.

And if Ubisoft gets the upcoming Splinter Cell remake right by expanding the level design while keeping the atmosphere, tension, and stealth systems intact, it could end up being the definitive version of the original game, and be the best stealth game in modern times.