Up From Darkness has one of the coolest premises for a pre-made adventure that I've ever heard: the players wake up in complete darkness, in a tomb, with no clue as to their identities or how they came to be in this horrible place, only to eventually discover that they brought it upon themselves and that it is a twisted initiation rite.
Of course, a good premise is only going to work if it has proper support. Luckily, the authors provided a decent amount of support for the wiggly, squishy, difficult-to-run amnesia situation, by providing, at specific points in the dungeons, instructions to give your PCs a memory "snippet" or "vignette," which can be found in the appendices. The vignettes are larger memories more closely related to the premise, while the snippets are random, unrelated memories which can be gained in any order, and serve to provide more of a nice backdrop. There are certainly more than enough snippets, and I think that this idea is very cool and will keep your players guessing up until the end, although I do feel that the final vignette, which is supposed to serve as the "big reveal," is a little anticlimactic.
The adventure also makes excellent use of the Kaidan campaign setting's take on restless spirits: the pre-made PCs (a great idea considering the amnesia angle of the adventure) come without their physical ability scores included. Instead, the crypt in which they awake has a number of bodies (around 4 per PC), and the PCs' spirits inhabit one at random. Should a character die throughout the course of the adventure, he gets a new body. At least, until the bodies run out. There is also an appendix supporting this, with "body cards" containing relevant statistics. I was a little confused that each body seemed to have a random bonus, like darkvision, +4 perception, etc., for no apparent reason (they were all human), but it does serve to make the bodies more interesting, even if it doesn't really fit the game's rules.
Sadly, the dungeon from which the party must escape leaves a bit to be desired. It makes heavy use of traps and haunts, which is great for the feel of the adventure, I suppose, but most of the haunts aren't a threat, and are just a nuisance, and while I'll admit that a pre-made adventure that pays any attention to traps is a rarity, I would have preferred to see at least a few unique traps, instead of all stock ones from the core rules.
Really, the thing that bothers me the most about the dungeon is that there isn't much in the way of memorable content. It's not a BAD dungeon, so much as it is a fairly bland dungeon. There isn't much in the way of read-aloud text to make the rooms come alive, and, for that matter, there isn't that much to most of the rooms except for "the encounter." While hardly a series of 10-ft.-square rooms with an orc guarding a chest, the dungeon didn't exactly feel inspired, to me.
The most memorable aspect is probably the middle part, a series of three encounters where the PCs must climb a series of long, vertical shafts filled with traps (and monsters). While this certainly had the potential to be fun, the dearth of flavorful descriptions really took a lot away from it, and, in conjunction with the free reincarnation available in the dungeon, I expect that most groups will see it as a hassle, rather than the thrill that it could have been.
Finally, it's worth noting that there are some definite technical glitches, which will bother some more than others, though it appears that a major section of at least one room is completely missing, which will prove problematic for anyone who wants to actually use the adventure.
Overall, with some work laid to add to the atmosphere and really evoke some interest in the dungeon, as well as perhaps spicing up the recovered memories a bit, this adventure could be a real treat. Taken as-is, without GM intervention, it will probably fall flat in several places, but should still make for an overall good time.
[3 of 5 Stars!]