Cold Ruins BF1
1 = Entrance.
X's = Go through these doors to get the switch marked "2" which will open door "3".
4 = Hit switch to open doors "5" & "6".
7 = Hit switch to open door "8".
9 = Get the countdown switch to open door "10".
11 = Stairway to BF2.
Cold Ruins BF2, BF3, & Small Room
12 = Entrance.
X = Hit all the switches to open door "13". Then go through and take exit to "14" and destroy the enemy hole there. Go back and door "15" will be open.
16 = Exit to BF3.
17 = Entrance.
18 = There's two switches in front of this door. ONLY hit the one on the right. That will open door "19".
20 = Countdown switch will open door "22".
21 = Hit the switch in front of this door to open it.
23 = Exit to the Bottom Floor.
Cold Ruins Bottom Floor
24 = Kill all the monsters on this floor to open door "25".