I want to start off by saying how much I admire the work and dedication put into this. Not only is it incredibly creative, well fleshed out and features a number of interesting and innovative uses of the game assets, but the actual mansion heist is one of the best I've ever played. The atmosphere, architecture, and the way the story unfolds is fantastic, and classic Thief noir stuff. Starting off in a small town with a festival, there's a murder, mystery, twists and turns... All great stuff, A+.

The first level is a great introduction to the campaign. Already the seeds are there for future treachery, and the way this town is introduced makes what happens later so much more visceral and effective.

And while I am completely on board with all of it, there are some frustrating elements that are easily overlooked at first, but begin to grow as you play along.
For one thing, there's a lot of key-hunting, which I've always found mystifying in a game where you have literal lockpicks. I get maybe one or two doors that might resist your finagling, but get the X key to get the Y key to get the Z key gameplay went out of style with 2D sprites. It's not too terrible, just a minor complaint... Until you get to mission 5!

Mission 5 reminds me of Hexen so much in that it's an endless array of switch hunting. This wouldn't be too bad, but this FM is heavy into forced ghosting, and you'll be going back and forth across these maps trying to figure out where you missed something that by the time you're an hour in, knocking out all the guards is the only way you can move around freely enough to do this.

Similar to the Soulforge gimmick, you have to throw a bunch of levers, so we're already off on a switch hunt. But just to throw ONE lever, I had to: (spoilers)

Shoot a moss arrow into a face carving(1), then throw a switch to do some platforming across a pit (2), then throw another switch(3), only to go back across the pit and throw a switch(4) to release a monster that required all my arrows to kill, then throw a switch behind it (5) only to open another switch(6). I throw that switch, then go to the other side and drag the monster body to use as a weight on a floor switch(7) to open another switch(8). (and dodge a trap that fires skulls at you, which honestly, that's worth a few redeeming points right there for being awesome,) and THEN I had to go back to the middle and throw a big switch(9) in order to open a ceiling panel so I could climb up hit another switch(10) with an arrow (had to waste a rope, thanks monster!) to then cross a massive gap and finally pull the original switch(11) I was looking for.
This was ONE of the big levers.

And this was the easier option, because the area I was searching was all in one temple. The rest are all spread out over the entire island, and I'm still looking for ways to open weird secret doors to get to secret switches to open secret doors to get keys to get to switches to open doors.

I don't want to take away from the labor of love of the author here, because the rest of the campaign is fantastic and full of great, classic Thief staples, and even new twists! Cutting a key out of the stomach of a corpse with a meat cleaver is maybe a little more Quentin Tarantino that I was expecting, but I'm on board.

This island, though... It will haunt me. Beware the Black Frog, and the infinity of switches.