FULL REVIEW:
Note: For anyone who doesnt know this pack is based on the old classic release:  "Zerstorer". It is highly recommended you play this if you havent already. :D

Aderlass (part 1)
This is a medium-sized, fairly squarish map in the Zerstorer bunker theme. It is tinged with copper and base, and instead of blood as in Zerstorer there is lava. You are given many looks at the evil red sky through windows and skylights. The texturing is good and interesting, and there are some areas where angles are used well. Lighting is also dark. Some might find it too dark, I adjusted my brightness settings a bit for this entire pack - dark atmosphere is good, but you have to be able to find buttons. The dark lighting, rock ceilings, and sometimes asymmetrical skylights give the map a feeling of being slightly larger and more mysterious than it is, which is good. Unfortunately none of these strengths can actually disguise the fact that the architecture is in 80% of the areas very blocky. Most of the areas are quite small too, so there's nothing visually impressive (that's rectified next map though!).

Basic combat against base enemies with, of course, the MegaEnforcer, provides a straightforward challenge in this map. I found it fairly easy, even though ammo was a bit scarce. The ending was cool. My overall verdict is, it's nice to see a map in the Zer style, but this map isn't really anything special.[12/20]

Aderlass (part 2)
You immediately emerge into a foreboding courtyard dominated by a breathtaking tower of rock, flesh, and metal. It even has a little blood-red stained glass window. The whole thing looks really awesome, one of the most impressive scenes I have ever seen in Quake. You journey inside, still no monsters, and the inside is very dark area made of creepy slimy blocks, just like in True Love Waits. In this map however you are ascending, not descending. As you progress through more dark, silent areas, the sense of foreboding is quite great. I haven't seen this "You are not supposed to be here" atmosphere done in Quake this well since the original Zerstorer. Suffice it to say, this is a creepy map.

When the happy event occurs, it actually was not as hard as I thought it would be (but then, could anything live up to the map's well established sense of dread?). Never the less, a decent challenge, even if it was a drop-off from the tense buildup. You then progress through more creepy areas where the theme shifts to flesh, and there is an extremely cool cut-scene to end it. Great map, unique, good use of moving brushes, and amazing atmosphere. I'm rating it highly because despite the unconventional approach and general lack of monsters it is a really great Quake experience.[17/20]

ZerTM_efdat
This map is also clearly influenced by True Love Waits, however, it is built in the Bunker style rather than the Green Slime style. You begin above ground, and descend through many levels of the bunker - a lot of the architecture is repeated, and simple, but that's not really a problem as you are basically just descending and ascending, finding your way down and back. The lack of monsters again builds mood, although not like in adrlass2.

When you reach the bottom, the fighting is actually a lot harder than in adrlass2. You have to be careful, not overly aggressive/stupid, due to the high amount of Shamblers. You are forced upon ascension to go from health pack to health pack - at least I was - fighting a lot of base enemies with the occasional Shambler to make things interesting. While it was quite hard and I died a couple of times, I never ran out of ammunition, and the combat situations were never ridiculous.

The lighting could have been darker/moodier, and there could have been more evil touches, but overall good fun. One thing which is good about this map is despite the complex layout with many areas looking similar, I never lost my way - the progression is really well done, and you definitely get a sense of going far underground. [14/20]

ZerTM_HT
This is the odd duck in this map pack, being based on neither Zerstorer's Bunker map nor on True Love Waits. Instead, it is a rather oldschool id map, in many ways like The Crypt of Decay, and also slightly reminiscent of The Nameless City. Some Zerstorer features are used (like statues, which are well done), but the feel is fairly id-standard. That, of course, is no bad thing. A mix of medieval textures gives the sense of a dungeon, with the fairly small scale making Hellknights (in particular) that much more efficient against you. Lava is also a danger here although I never fell in (except when I was supposed to).

Progression is fairly straightforward, with medieval monsters and Zerstorer features used. Plenty of chances for the unwary or lazy player to die. You get both keys and progress through a few different vertical levels. Skylight is well used. Nothing visually great, but every area is tidy, well-designed, and looks good.[14/20]

overall scores:
Aderlass (part 1) 12/20
Aderlass (part 2) 17/20
ZerTM_efdat 14/20
ZerTM_HT 14/20