God Mode  -  Pause the game and press DOWN,Y,X,R,RIGHT,L,LEFT,B
Warp to any level  -  Right,Left,Z,R,Z,L,Z,C 
Full map  -  B,B,C,Left,B,B,C,Right 
All items and enemies on map  -  B,B,C,Right,B,B,C,Left 
All guns  -  B,Y,X,L,R,C,X,Z 

Level Health Armor Weapons Password

2 - Plant 125% 200% All CR!3WDD3DB
3 - Toxin Refinery 200% 200% All 3JJCMK8W64
4 - Command Control 200% 200% All 03LTJ0Y!02
5 - Phobos Lab 200% 200% All H33!1HFTHK
6 - Central Processing 200% 200% All 04MSKZX9Z1
7 - Computer Station 125% 200% All YTTLCXXLXV
8 - Phobos Anomaly 200% 200% All 09SMBY04YW
9 - Diemos Anomaly 200% 200% All 7KKBLD7V53
10 - Containment Area 100% 200% All FM4217GSGJ
11 - Refinery 200% 200% All H!!3WDGLDB
12 - Deimos Lab 200% 200% All 07QPDW26WY
13 - Command Center 350% 150% 1234 6 WTXQ9C3W12
14 - Halls of the Damned 100% 200% 123456 RBR4G!LDLN
15 - Spawning Vats 300% 175% 123 6 WTXQ9C3W11
16 - Hell Gate 50% 75% 1234567 548C7DFWYX
17 - Hell Keep 100% 125% 1234567 JOC89DZPQS
18 - Pandemonium 100% 125% 1234567 JGB9CT0NRT
19 - House of Pain 100% 200% All 9QLTKR0!02
20 - Unholy Cathedral 100% 200% All 78M63QX921
21 - Mt. Erebus 200% 200% All S!61FHVQJG
22 - Limbo 200% 200% All 33QHFTT6WY
23 - Tower of Babel 200% 200% All VBGQPJ!Y46
24 - Hell Beneath 200% 200% All ZYKTLW7V53
25 - Perfect Hatred 200% 200% All 0DJSM4HW64
26 - Sever the Wicked 200% 200% All LS5YPTCRKH
27 - Unruly Evil 200% 200% All ZDJSMVRW64
28 - Unto the Cruel 200% 200% All 1YKTX4QV53
29 - Twilight Descends 200% 200% All XKF6R8LZ97
30 - Threshold of Pain 200% 200% All DJX07Q4HTR
31 - Entryway 200% 200% All C0W1!QNJQS
32 - Underhalls 125% 200% All VM!3V1D3DB
33 - The Gauntlet 150% 200% All W394W2DMFC
34 - The Focus 150% 200% All ZQ58ZKJRKH
35 - The Waste Tunnels 175% 200% All Z758ZKJ8KH
36 - The Crusher 200% 200% All 5C2V3DQBNL
37 - Dead Simple 200% 200% All NCKBLX7V53
38 - Tricks and Traps 200% 200% All 1Q580FCRKH
39 - The Pit 100% 200% All HTMSKZZ9Z1
40 - Refueling Base 200% 200% All WS58ZKCRKH
41 - O of Destruction! 200% 200% All CSNRG2W820
42 - The Factory 200% 200% All WT670JBQJG
43 - The Inmost Dens 200% 200% All DQLTJ1Y!02
44 - The Suburbs 100% 200% All 2N94VFFMFC
45 - Tenements 200% 200% All CQLTJ0Y!02
46 - The Courtyard 200% 200% All WR492GDSGJ
47 - The Citadel 200% 200% All PFFGXH3777
48 - Nirvana 200% 200% All JWCJV2X479
49 - The Catacombs 200% 200% All CJJTM35964
50 - Barrels of Fun 200% 200% All M!T174XZXV
51 - Bloodfalls 200% 200% All 5770MX2CDF
52 - The Abandoned Mines 200% 200% All YJLW3PPCPM

Mid Level Options Screen  -  Pause the game, hold directional right and button A at the same time. 

Secret Levels

The Military Base: P7WTK!GF12
Fortress Of Mystery:1XY!PCKNTR
The Marches: NMLCJSGXZ1
The Mansion: YCW1!QQJQS
Club Doom: CKFGR93Z97