Upper Dorn's
Miconids - can cause problems if they make someone berserk and they do a lot of damage *if* they hit. Protect your mages and just hack through them.
Ettins - tough guys. But slow
http://www.gamebanshee.com/ubb/biggrin.gif Tank & archers here. Don't be afraid to give ground.
The bridge - this U shaped chamber is a tough fight too. However, it is possible to take out the orc archers on the arms of the U first with missiles & magic. Then draw out the Neo-orogs & Drow spellswrods. Missile weapons are a must if you're to drop the Drow Spellcasters. Their mirror images can be dropped with dispel magic or magic missile. Blast the remainding Orogs & orc marksmen with a fireball.
Neo-Orogs - Easy to kill but the warlords are quite tough.
Drow (Spellswords, Vanguards & spellcasers) - hard fights here, though there are only a few. Magic is all but ineffective. Their crossbows are poisonous. Its potion & defensive magic spell time again. Take down the spellcasters with missiles. Close with the vanguards to prevent them using their poison. Deal with the spellswords last. Make no mistake, these are tough fights and you have to deal with 3 groups of Drow.
Undead & Lich - Deal with the undead as before, hack through the cadavers. Any cleric should be high enough to destroy skeletal undead outright. The best way to take out the lich is with haste spells & strength potions (this is a good strategy for defeatingany powerful character, deal out lots of damage quickly) - he may get you with a few fireball-type spells which erupt from his position. You should find the key in the coffins *first* with thief. Kill the lich at least once for the experience then hide your party in the tombs whilst your thief locates the phylacteries and destroys them.
Bronze Guardians - more tough creatures. Haste & strength, magic & missile weapons hardly scratch them. See why you need fighters?
http://www.gamebanshee.com/ubb/biggrin.gif