I've already played into this addon long ago. However I stopped playing short of the end due to one issue that really spoiled it IMO: backtracking - or more like, EXTREME backtracking. On nearly EVERY level, it seemed to go like this: go to one end of the map to get the first key, then go to EXACTLY the opposite end for its key door, then once you have the second key you must go back probably near where the first key was (opposite side of the map entirely), and so on. In short, it seemed that EVERY time you got a key, you would have to backtrack virtually the ENTIRE map (or at least what you'd seen of it so far). That was for four keys per level, so on average you'd be running for one side of the map to the other four times, and they are big maps at that.
What's worse IMO is that there were no guards or anything, just a minute or more of running around every time you find a key. Clearly I believe this was the intent of the mod's author, because it is such a persistent feature. But this release seemed to be received fairly well nonetheless, and it even won a Dome award. So did you notice this "go from one end of the map to the other every time you get a key" issue, and if so, did it bother you/taint the set overall as it did for me?
Regardless I really felt it was a shame, because otherwise the maps were very well put together.