Went through the entire Thief series
Thief: Gold
What can I say about this game that probably hasn't been said a million times? Great ass level design, good stealth mechanics, moody as hell atmosphere, amazing music, and the freedom to approach any level the way you want, or at least most of them. Writing is nothing spectacular, but it's a nice build-up to the twist. Thief's supernatural elements are included in the way that I like them best, minimalist -- where it exists, but it isn't meant to be a part of everyday life. Thief 1 is a definitely a point where they created a framework and managed to do the best they possibly could with what they had.
Thief 2: The Metal Age
But overall, I find myself being more keen towards Thief 2 in general. Admittedly, the lower points are lower than in Thief 1, but there's more than enough to make up for it everywhere else. Thief 2 basically took the framework of the first game, and increased the complexity of objectives in each level after giving you two introductory levels. Whereas Thief 1's missions mostly played out in a straightforward manner, Thief 2 goes out of its way to essentially start subverting your expectations for a how a mission will develop. It becomes a bit of a hassle in later levels, but the only one that feels obnoxious is Sabotage at Soulforge.
I'd also say the writing is more noteworthy in this game in comparison to its predecessor. Notes that you find in the missions are actually interesting and even relevant to events that happen later on in the game. The world is much more fleshed out in this game as is the worldbuilding, and it is apparent very early on in Framed when you find notes that refer to the internal conflict within the city watch, which actually come into play later on with Blackmail and Trace the Courier. I was also a bit of a fan of how the events of the first game were directly responsible for shaping what happens in this game with the Hammerites and the Mechanists, and I honestly think this is what elevates the game for me over Thief 1.
Thief: Deadly Shadows
The weakest of this trilogy, but it's still pretty good in its own way. Deadly Shadows is more interesting to think about what they changed than it was to actually go through. Levels are bite-sized chunks of the bigger levels in previous Thief games, and as a result, some of them end up fairly linear despite still having the same core framework. Main difference here is that instead of level-based missions, you are free to explore the city in between missions to do side-quests or to just to get more loot. The city itself isn't that interesting to explore, but it was nice to see the progress in terms of AI where you could walk around normally with regular civilians, and would have to hide from the City Watch.
Dynamic lighting system would've been a great addition if they had done more with it. The House of the Widow Moira is one of my favorite levels partially because of how the lightning strikes will momentarily illuminate you, but unfortunately that whole system is never used in an interesting way other than giving guards torches. Cradle is also a nice change of pace, and a pretty great level except for the tail end of it where it outstays its welcome, but other than that, there's still some gems in this game.
Thief (2014)
Fuck this game.