Really atmospheric stuff in here. What "A Thief's Training" does with visuals is really impressive, as it brings into broad daylight arguably the darkest game in the series, and one of its darker themes as well. Both the little city section and the compound look very good and you get some brilliant sunlight effects, which are rare even in T2 FMs, not to mention TG.
A minor grumble - for some puzzling reasons, the author decided to use Deadly Shadows' ambient music, which to me is a no-no in TG normally, let alone in an FM meant as a "homage to Dark Project." It doesn't spoil the experience in any way, it just seems completely out of place.

It is a mission you'll want to take your time with. Soak it in and calmly and thoroughly look everywhere to discover all what it's got to offer. There are some adorable bonus objectives outside of your list, and many clever secrets around. The places you visit don't once feel too crowded (at least on Hard), nor are the objectives restrictive, so pretty much all gameplay styles are welcome. Also, the few puzzles you got to deal with feel rather accessible, so that's a good thing. There is however the technical problem with the statues, as mentioned in the mission notes. Now, I'm a heavy clicker in Thief, so even having read the notes beforehand, when I realized it was *that* place it was already too late as I'd already broken the mechanism, and ultimately had to resort to 10 minutes of random clicking. While I understand it might be an engine issue, it obviously shouldn't work like that for a player.
Once you enter the complex, the locations start feeling labyrinthine, but the relatively small scale of the place prevents this from being a problem. One major layout issue is that I wasn't able to come back to the starting area after I'd left it, and the mission doesn't appropriately indicate that you're leaving the quarter for good. Save for the statues issue, the mission plays very good throughout.

Story-wise, there are some heavy references to The Black Parade, and the narritive style feels generally very similar. Nothing especially original about the locations, as Keeper compound missions come in droves and there isn't anything striking in this particular one. It feels unique enough, however, as the entirety of it is shown in different light (excuse the horrible pun).

Overall, a nicely designed and very atmospheric mission you'd never expect is a first. Not very challenging in it's primary objectives, but a lot of fun with all the side/hidden stuff.

Thanks for your review and interesting insights.

I would just add one clarification - you can return to the starting area if you have a rope arrow (some arrows are available in the compound). An exit point to end the mission is also available at the original starting area, so this was intended as an option for players to return to.

Thanks, should've double checked that. My path to the compound was already a bizarre one as I never used the door I was apparently supposed to ¯\_( ͡° ͜ʖ ͡°)_/¯

You can go back to the starting area even without a rope arrow though. It's a bit tricky and you probably need several attempts, but you can jump up.