A Midsummer Night's Heist is your classic Burglary Simulator experience, the kind of map I love: No undead BS, no weird surprises, just a foppish oaf with a big house and lots of valuables. Excellent. An optional (yet still compelling) objective exhorts you to knock out no more than two people, and the rest is a standard one-big-target-plus-X-loot combo.
The map is well designed with many openable escape routes, secret passages and avenues for vertical traversal such that movement feels fluid and dynamic (bring rope arrows, you will use them). The layout of the building makes sense and although there is no automap the static map you are given is clear enough and the level small enough (as it should be, given the rules of the contest) that this isn't a problem.
Loot scarcity, however, does present a problem. I scoured the map for an hour looking for the final gem to fill the secondary loot requirement. Even now I'm convinced that the expert level for that objective requires finding every single gem in the level, including those in secrets, which is certainly "Expert" level difficult but also feels cheap and non-Looking Glassey. Secrets are, after all, supposed to be optional. The telegraphed power station key from the beginning of the level was also not forthcoming, not being found in any of the places the readable that revealed its existence might have been referring to, but thankfully it isn't required to complete any objectives.
As far as the story goes, it is well set up, decently written, mostly telegraphs in-game points of interest well and paints a strong (if simplistic) picture of the attitudes of the people of Bohn and Sir Vasko's household. It's the usual stuff, though, and doesn't go far beyond explaining the map itself. A pretty great detail is the spectacular VO impression of Stephen Russell in the briefing video- my friends and I could barely tell the difference.
AMNH is well worth your time if you like Thief II to be on the Fantasy Burglar Simulator II side, but beware the stingy objectives.
Sorry but this review is factually wrong. Looking at the lootlist I made for it, you certainly don't need to find every gem available in the mission to fill the gems quota, and you don't even need to find any secrets to reach it. You also mention that the key in the sewers is not found where the readable says, but it literally is found where the readable says it is, and in a logical location to boot.
Also, if I remember correctly you do need to find a secret compartment in Thief 2's Running Interference to reach the gems quota in that mission, so mandatory secrets in the game aren't unheard of. In any case, I find it a bit unfair to dock points from this mission because you didn't look hard enough for loot that isn't placed in secrets and isn't that hard to find.
To be clear: I haven't docked any points from this mission for not being able to find loot. Only the title is harsher than I would like, and that cannot be changed. I was conscious that, although I looked for the missing loot for a long while, I was privately streaming at the time and couldn't be *quite* as thorough as I usually am taking levels apart for loot because at that point the action stalls and it makes for a dreadful viewing experience. That said however, I feel that there surely must be a room I was missing or something of the sort if the loot was not that hard to find, because all five people in that stream agreed I had completely scrubbed every room they had seen up until that point and traversed the entire house multiple times and there was simply nothing else remaining.
I found the key just now, looking for it specifically in one of the three places the readable implies at your recommendation, but only by turning my gamma up incredibly high. On normal brightness it is completely invisible and very small, and cannot be taken from the safety of a dark area. But again, it is not required to complete the mission, and there are plenty of viable escape routes and entry avenues available without it, far more even than most other FMs would provide, so it doesn't factor into the score on my review.