Witchaven II: Blood Vengeance/Level 12: Crypt of Decay

Up the stairs from the start, you'll find a room with four floor pads that open up side closets with enemies waiting inside. You may want to hit at least the south and east pads to open up the closets which have pull chains; one opens an armory with some nice gear to get yourself up to speed if you're starting this level fresh, the other has what seems like a lifetime supply of fireball scrolls. You might want to toast lots of enemies in this map and return here periodically to restock, unless you're going for a speed finish. Hit the other pads if you're thirsty for battle, then move on.

For the glass key, follow the spiral stairs all the way up and head north to the outdoor ramparts area. You'll find it on the central structure, right by the exit pad, but since you don't have the pentagram yet, you can't leave.

Go back to the spiral stairs and down a floor to the throne room. The glass key door is down a narrow passage next to the bookshelf. Go through and grab the pentagram.

You can now return to the ramparts and leave if you wish, for a quick completion albeit one that misses much of the map.

Tips and secrets:
 * In the room with the stockpile of fireball scrolls near the start, jump behind the fire altar to get a cure poison potion and a health potion that might come in handy if you got hit by the imps or trap in this room.
 * Step on the throne to open a chamber with a fireball spell and a diamond ring.
 * The black key is found on one of the side ramparts of the exit area.
 * The black key door is found through the passage behind one of the closets that opens if you hit the floor pads near the start; head to the end of the passage before you turn off (the other fork leads eventually to the throne room). Through the door is a dungeon with a Mino Drake and a measly health potion.
 * The brass key is also in the rampart area. When heading there from the spiral stairs, take the right-hand path and go up the ramp.
 * The brass key door is in a wooden area that can be conveniently located by going into the passage behind the throne and turning right. Behind this door is a small chamber with a hoard of gold waiting for you.

Notes:
 * An interesting map for a couple reasons; for one, it makes much greater use of BUILD's ability to overlap sectors than most of the maps, and secondly, it has several of the patrol point objects that were rarely put to use (the patrol points, however, may not actually function).