Quake 64 cheats and cheat codes for Nintendo 64

Go through walls:
Enter "NOCLIP" to enable No clip mode.

Unlock Debug option in options menu:
Enter password: "QQQQ QQQQ QQQQ QQQQ". Ignore the "Incorrect Password" 
message. You can access stage select, invincibility, all weapons and 
monster targeting cheat options.

Maximum weapon and level passwords:
Type any of the following passwords to begin a new game with maximum 
weapon on the indicated level. 

Level - Easy
Realm of Black Magic - ?DRY OPFG P3BT VBKX
The ElderWorld - 95RV TPFG QQBT JBJT
The NetherWorld - 81RV 6PFG RGB5 5BJH
Shub-Niggurath's Pit - 79RV 2PFG R7BS SBJF

Level - Normal
Realm of Black Magic - 6DRW OPFG T3BR VBJX
The ElderWorld - 5SR9 TPFG VQBR JBCT
The NetherWorld - 41R9 6PFG WGBQ 5BCH
Shub-Niggurath's Pit - 39R9 2PFG W7BQ SBFC

Level - Hard
Realm of Black Magic - 2DR? OPFG Y3BP VBCX
The ElderWorld - 1SR7 TPFG 2QBP JBBT
The NetherWorld - 01R7 6PFG 0GBN 5BBH
Shub-Niggurath's Pit - Z9R7 2PFG 07BN SBBF

Level - Nightmare
Realm of Black Magic - YDR8 OPFG 23BM V3BX 
The ElderWorld - XSR TPFG 3QBM JBFT 
The NetherWorld - W1R5 6PFG 4GBL 5BFH 
Shub-Niggurath's Pit - VR95 2PFG 47BL SBBF 


Level - Name - Password:
2 - Castle of the Damned - H40X ZVVB HLBD 74DJ
3 - The Necropolis - H0P3 2XBN WQ2B NZVK
4 - Gloom Keep - CWHX CH3B GDB3 14JY
5 - The Door to Chthon - PQW4 9QVD Y8VY X21M
6 - The House of Chthon - PL24 XBBT YJLQ 32?6
7 - Ziggurat Vertigo - 6JR3 KDDV 3SLG 9RFT
8 - The Ogre Citadel - GWY6 7BBB 23BD L4HK
9 - The Crypt of Decay - B8YN BBBB ZBBB SXR4
10 - The Wizard's Manse - 55R6 0XCJ 2LBR QVV1
11 - The Dismal Oubliette - 51RZ ?6xQ RGBR NNJH
12 - Underearth - 5XRV SMXP B7BR LP5H
13 - Termination Central - 5SR9 TPFG VQBR JBCT
14 - Vaults of Zin - 5NRV JF6G CVBR GBFL
15 - The Tomb of Terror - 5JR6 HDXM 2ZBR DPN5
16 - Satan's Dark Delight - 5DR0 HW4N PZ?S 5Y2W
17 - Chambers of Torment - 49R6 XBBJ 2GBQ 932T
18 - The Haunted Halls - 45RZ ZF32 LZBQ 773R
19 - The Tower of Despair - 41R0 6PFG WGBQ 5BCH
20 - The Elder God Shrine - 4XRV QBFG B3BQ 3BD3
21 - The Palace of Hate - 4SR5 DBBN ZGBQ 1628
22 - The Pain Maze - 4NRV JBBF BRY5 744W
23 - Azure Agony - 4JR5 1BBB 0QBQ X4HX
24 - Shub-Niggurath's Pit - 39R9 2PFG W7BQ SBCF
25 - The Nameless City - 4DR1 4XDD RVBQ VM1B