This mission is rather unusual. It doesn´t offer "classic" Thief gameplay - or at least only a fraction. It is a riddle mission that reminds me of the Cube Escape/Rusty Lake games. This means: A horror setting, a dark background story, and riddles to solve, with a lot of hidden things.
There are not many enemies - you will encounter a handful of Burricks in the beginning, but they are the least dangerous foes, because with mission progression some others will spawn(a good idea as it also works for the climax), but most time you can explore the area without danger.
There is some loot in the mission but it´s not the most interesting part - as there is no loot objective you might also skip it.
As you don´t play Garrett but Ortis, there are also custom player character effects(with only a few being standard Garrett sounds, maybe an oversight).
One thing I like are the aesthetics of the mission. The overall vibe is gloomy, music is only sparsely used, and it really feels like a haunted house.
Custom voice acting and the few but sufficient writings tell the story.
Some of the riddles might be challenging, especially the search for certain symbols is not easy.
At some parts it might get a bit frustrating, and the ways through the house are sometimes a bit annoying, as some of the require rope-arrowing. What also at some points is annoying that you get stuck at certain things on the floor. With a bit more polish for these aspects the mission would have been better, but fortunately it´s not a gamebreaker.
Still, overall, this mission is enjoyable, if you are looking for a different Thief experience. I wish there were more in this style, too bad the author seems to have only made this one.

I personally haven't played Cube Escape series (maybe, in future), but if you like Coaxing the Spirit, - there is another FM Rose Cottage (also for Thief 2) by Saturnine - it is also big puzzle horror mission with distinct graphics and atmosphere (at least until the Big Reveal). Another a bit similar mission is Eclipsed by HipBreaker (for Thief 2, more open horror city mission). Some Haplo's missions (that series that begins with Unholy Vivid Innocence)...

Ok, I will check them out.
You can also check out the Cube Escape/Rusty Lake games easily as most of them are for free(Steam and the two big mobile OS stores).

Thanks!