To unlock the levels in the game without having to spend hours playing the game just enter the following codes at the 'Password' screen.

Unlock Level 02 - CR!3WDD3DB

Unlock Level 03 - 3JJCMK8W64

Unlock Level 04 - 03LTJ0Y!02

Unlock Level 05 - H33!1HFTHK

Unlock Level 06 - 04MSKZX9Z1

Unlock Level 07 - YTTLCXXLXV

Unlock Level 08 - 09SMBY04YW

Unlock Level 09 - 7KKBLD7V53

Unlock Level 10 - FM4217GSGJ

Unlock Level 11 - H!!3WDGLDB

Unlock Level 12 - 07QPDW26WY

Unlock Level 13 - WTXQ9C3W12

Unlock Level 14 - RBR4G!LDLN

Unlock Level 15 - WTXQ9C3W11

Unlock Level 16 - 548C7DFWYX

Unlock Level 17 - JOC89DZPQS

Unlock Level 18 - JGB9CT0NRT

Unlock Level 19 - 9QLTKR0!02

Unlock Level 20 - 78M63QX921

Unlock Level 21 - S!61FHVQJG

Unlock Level 22 - 33QHFTT6WY

Unlock Level 23 - VBGQPJ!Y46

Unlock Level 24 - ZYKTLW7V53

Unlock Level 25 - 0DJSM4HW64

Unlock Level 26 - LS5YPTCRKH

Unlock Level 27 - ZDJSMVRW64

Unlock Level 28 - 1YKTX4QV53

Unlock Level 29 - XKF6R8LZ97

Unlock Level 30 - DJX07Q4HTR

Unlock Level 31 - C0W1!QNJQS

Unlock Level 32 - VM!3V1D3DB

Unlock Level 33 - W394W2DMFC

Unlock Level 34 - ZQ58ZKJRKH

Unlock Level 35 - Z758ZKJ8KH

Unlock Level 36 - 5C2V3DQBNL

Unlock Level 37 - NCKBLX7V53

Unlock Level 38 - 1Q580FCRKH

Unlock Level 39 - HTMSKZZ9Z1

Unlock Level 40 - WS58ZKCRKH

Unlock Level 41 - CSNRG2W820

Unlock Level 42 (The Factory) - WT670JbQGJ

Unlock Level 43 (THe Inmost Dens) - DQLTJ1Y!02

Unlock Level 44 (The Suburbs) - 2N94VFFMFC

Unlock Level 45 (Tenements) - CQLTJOY!02

Unlock Level 46 (The Courtyard) - WR492GDSGJ

Unlock Level 47 (The CItadel) - PFFGXH3777

Unlock Level 48 (Nirvana) - JWCJV2X479

Unlock Level 49 (The Catacombs) - CJJTM35964

Unlock Level 50 (Barrels of Fun) - M!T174XZXV

Unlock Level 51 (Bloodfalls) - 5770MX2CDF

Unlock Level 52 (The Abondoned Mines) - YJLW3PPCPM

Unlock Level 53 (Monster Condo) - DKKBLM58J3

Unlock Level 54 (Redemption Denied) - 7L3!266DJK

Unlock Level 55 (Fortress of Mystery) - 4680Q7B5BD

Unlock Level 56 (The Military Base) - T3QP7W26WY

Unlock Level 57 (The Marshes) - RNSM5YYMYW

Unlock Level 58 (The Mansion) - HWKB!57V53

Unlock Level 59 (Club Doom) - 644YL1Q9GJ

During gameplay pause the game and enter the following codes.

Unlock God Mode:
Down, L2, Square, R1, Right, L1, Left, Circle

Unlock Full Guns and Ammo:
X, Triangle, L1, Up, Down, R2, Left, Left

Unlock Level Warp:
Right, Left, R2, R1, Triangle, L1, Circle, X

Unlock Full Map:
Triangle, Triangle, L2, R2, L2, R2, R1, Square

Unlock Map with Objects:
Triangle, Triangle, L2, R2, L2, R2, R1, Circle

Unlock X-Ray Goggles:
L1, R2, L2, R1, Right, Triangle, X, Right