The start of the map was no indication of what was to come. I liked the little ambush of Knights but it would have been good to lock the player in the sloped corridor by then, to make him panic and want to run ahead (only to bump into the worse).
I kind of got lost trying to get the lower of the two buttons, looking where to fall down before realising there's a hugeass ledge just on the right (I'm that awesome). Then I tried to get the second button and got headshot by the Fiend :( I found the teleporting floors to be fairly fresh, even though they needed to be used more often.
I also felt that the use of enemies was slightly inadequate at times. Some of the Vores should have been Droles (or Death Lords), some of the Droles should have been Shamblers, etc. The Ogres standing on the pillars rising out of the lava could benefit from being Flak Ogres, too, I think.
I did love the small details this map had. The pentagram platform with the Death Knight was cool, and so was the pentagram lift in the corner opposite. The flesh closet with the Drole was just perfect, it gives you the feel that Droles are totally fucking otherworldly even to what you've seen before - a Fiend/Vore/Shambler in that closet wouldn't have had nearly as much impact.
Probably the best out of all Lost Chapters :P
PS. Whatever happened to this map? http://necros.planetquake.gamespy.com/ne_doom2.jpg