Sever the Wicked review, 0.28 from steam (latest as of 2012-12-30)
I've just finished playing sever the wicked and here is my review. Part of the review contains details that can be considered mild spoilers, so it is hidden.
First and foremost, this dugneon IS NOT FINISHED. At one point you just descend into the next level and see dead end with a comment that the mod was designed by tension69. That is a major drawback for completionists. Another appropriate warning is that author of this mod quit Grimrock modding! It won't be finished and bugs will remain unfixed. Keep that in mind when starting play of this dungeon.
It took me 3,5 hours before I hit the "end", i.e. empty deadend. I was severely disappointed with that.
This is one of the oldest dungeons, but it is quite advanced and shows number of excellent tricks. It is a proof that it's possible to design a climatic dungeon without torches. There are many other light sources, with some of them very nice and uncommon. Author knows how to set the mood with faint lights and shadows cast by scary figures. It scores extra points for not letting the player ruin the experience with torches.
This mod tweaked some enemies. Some are trivial to kill, but others are extraordinary difficult. It is a very clever design. One enemy is so powerful that players barely scratch him. However, there is a secret that once revealed helps tremendously to survive that fight. If you're trying to speed run this - you'll die one way or the other - get killed or die out of frustration

Take your time and look for secrets. Some of them are very well hidden.
There are many modified items. Some new food names made me laugh.
There are excellent puzzles there. But be warned - some of them are far from being trivial. Solving puzzles gives you experience, which is nice. It gives a good balance between fights and exploration.
I played this mod with a fresh standard party - 2 fighters (minotaur + human), rogue and mage. I highly recommend having at least one mage in your party. There are significant disparities between certain classes. Some of you may be out of luck here. I'm looking at you - thieves, rangers and pathfinders

I actually like it that way. Life is not equal for everyone and 2 meter tall minotaur with double axe is likely to have better chances of survival than a weak, small gnomish scribe or a bard (sorry, Bard's tale fans

.
There are several comments around that food was scarce. I found that not to be the case. I suppose author fixed that before he left.
I hit several bugs, some of the crashing the game. There are known workarounds for them, so it does not completely ruin the experience.
Bugs:
Bug 1: I was able to find 4 treasures out of 3.
Bug 2: One of my champions was dead, but I found a secret and everyone got experience, including the dead guy and he leveled up.
Bug 3: On level 6, player is supposed to put dragon statues on altars to stop the dragon from spitting fireballs. Attempt to pick up the dragon will crash to desktop with the following error:
#script_entity_37:3: attempt to index global 'drgspit6' (a nil value)
stack traceback:
#script_entity_37:3: in function <#script_entity_37:1>
[string "ScriptEntity.lua"]: in function 'onMessageReceived'
[string "MessageSystem.lua"]: in function 'sendMessageToEntity'
[string "MessageSystem.lua"]: in function 'broadcastMessage'
[string "TriggerEvents.lua"]: in function 'fire'
[string "ObjectContainer.lua"]: in function 'entityRemovedFromCell'
[string "Altar.lua"]: in main chunk
[string "MessageSystem.lua"]: in function 'sendMessage'
[string "Map.lua"]: in function 'removeEntity'
[string "Item.lua"]: in function 'onClick'
[string "GameMode.lua"]: in function 'mousePressed'
[string "GameMode.lua"]: in function 'update'
[string "Grimrock.lua"]: in function 'display'
[string "Grimrock.lua"]: in main chunk
The easy workaround is to leave the dragon statue on the altar.
Trivia:
you can meet Komag, Antti and Petri in this dungeon, but I find their medical condition highly unfortunate.
Summary:
It is a shame that this very promising dungeon is unfinished. I think there are no sources available for it, so there is no hope for other modders to finish it up. There are excellent, difficult, but rewarding puzzles, great lighting and mood in general and nice balance between fight and exploration. I highly recommend other modders to play through this dungeon. You can learn many tricks from it, especially regarding mood and lighting. As for regular players - well, you can't finish it, so think twice before you start your adventure here.