Like others have said, this game was top notch, probably one of the best 3 we've ever done. The puzzles were difficult enough to be very challenging, but there was a flow to them that made each make enough sense that we were never completely and totally baffled.
Flow was excellent. Probably the best I've ever experienced. The puzzles were novel. We had a group of 7 experienced escape room players with different players having different puzzle solving strengths. There was enough variation in the number and types of puzzles that we all felt like we contributed significantly to the solve.
Yes, the GM was excellent. We chatted before and he helped explain the puzzles in depth afterwards for puzzles where we got it, but there may have been some hidden clues that we didn't discover along the way.
Particularly interesting or different
Yes
Overall, I found it medium-hard. Of the 7 in our group, each puzzle was something that at least one or two players found fun and interesting, so they were happy to drill down on it and solve it. I think we got a bit lucky in that there were a couple of puzzles that we sussed out in a reasonable amount of time that if we hadn't figured out a pattern or clue, we would have taken a lot longer and found it much harder.
There is some tech, but there's not a "high tech" game.
There is a bit of a ghost element, but it's not particularly scary. I'd call the storyline and first 1/4 somewhere between "not scary" and "spooky", and the rest of it is firmly "not scary".
Physically active
Somewhat