Well I gave it my best shot. Despite hearing bad things about this game, I am a huge fan of the Looking Glass originals and I really wanted to love this. Even if the game mechanics were bad I was still excited to immerse myself back in the world of the original Thief games. I am so deeply disappointed. After playing for around 6 frustrating hours I have finally rage-quit and I can't do it any more. I got it for a bargain on a steam sale, around $2 but I feel like even that is asking way too much for this abomination.

There are so many things wrong with this game I don't even know where to begin. The entire game and every part of it is broken but I'll try to address some of the more irritating/awful elements.
Firstly, the game is literally broken and filled with bugs, mostly related to the sound engine. Disappointing for a AAA game. Often I'll be standing directly in front of a talking NPC and I can't hear their voice. Some sounds are missing. Sometimes I'll hear something extremely loud, like a deafening snoring sound of a guard who's asleep 300 meters away. Other times the sound engine just breaks and the game goes silent.
One of the best things about the original Thief was the sound engine. Sound was a central part of the experience: you listen carefully for guards, your own footsteps, doors, etc. and you act accordingly. This game, even though it was made 15 years after, has a worse sound engine, it's just broken and the actual sounds and the 3D effect don't really work; sound isn't an element of the gameplay at all. Furthermore the player is given all these ridiculous super powers. He can see through walls, see in the dark; every lever, button, loot, etc. is highlighted in blue (with x-ray vision) by pressing a key.
The game mechanics are also broken, although this is a design feature. The original Thief games were brilliant because it was so open. Not open world, but each level/mission was a gigantic open area, literally huge. You could explore the entire region, scouring it for loot, alternate passages, secret rooms, etc. In this game you spend a third of your time in loading screens. The entire game is pretty much a linear hallway of small poorly-designed levels, connected by long loading screens.
Another third of the game is QTEs. I kept thinking: am I playing a Thief game or is this Cookie Clicker? Any time you want to do something, even simple things like pulling a lever or opening a window you have to go through these repetitive offensive QTE events. Sickening.
In the original Thief you could shoot a rope arrow into most surfaces and scale up on to roofs, ledges, over walls or scale any object in the level. In this game that feature has been almost entirely removed: Garret CAN'T EVEN JUMP! And the levels are filled with invisible walls at every turn. There will be a ledge only a meter away, a waist-high fence, or a crate or a nearby rooftop; no you can't access these areas, invisible walls. He's an expert Thief but he can't jump over a couple small crates?
The control of Garret is also extremely slow and frustrating. Every time you want him to do something (like pick a lock, pick up some loot, open a door) there's a huge delay and the (for example) opening a door animation is really slow and drawn-out. You're supposed to be a lithe Thief, fast and agile; instead I feel like I'm controlling a tank or perhaps grandma with the wheelie walker. Everything is slow and he can't even jump over a low railing. Absolutely infuriating.
All of this I could forgive, I could ignore it if the game had a good story, setting or atmosphere. But they didn't even get that right. The original games had such a strange mysterious setting, like a parallel universe steampunk Medieval/Victorian England. There were strange cults, seedy characters and then the supernatural element: ghosts, zombies and burricks. For this game the feeling just isn't there. It's like they've copy-pasted Assassin's Creed, there's no individuality or style. The whole game just feels like a bad "Medieval Britain" Unity asset. The narrative is boring, predictable and uninteresting with the most offensive and contrived romance sub-plot I've ever witnessed. Garret, instead of looking like a cool mysterious figure looks like a goofy 40 year old weeaboo in cosplay. He's no longer cool or mysterious; his dialogue and voice acting paints him as this stereotypical "stoic tough-guy." Of course they removed all the interesting parts of the universe: the steampunk, paranormal, skeletons, ghosts, magic, the cults, the Hammerites, the Keepers, etc. That's all gone, there's no atmosphere, or mystery, it's just ugly and uninteresting, a cookie cutter medieval world filled with all the tropes you might expect. I don't know how they made such a mess of this, were they even trying? Are the developers trolling me?
There was a great opportunity here to reboot this series but they dun goofed. Big time. It actually makes me sad; they should have packaged this title under a different brand because it's an insult to the original series. I'm deleting it off my hard drive; I would give it zero stars if that option existed.