Enable Features menu and start new game with everything
Press Start to pause the game, select Options to bring up the Options menu, select Password, and enter one of these passwords. Each password enables the Features menu (cheat-options menu), and gives the player 200% health, 200% armor, a backpack, maximum weapons and ammo, and all 3 Demon Artifacts.

Start with Everything at "BE GENTLE!" Skill	?QDM 7HYC BB4X FJVB
Start with Everything at "BRING IT ON!" Skill	?LD4 7HYB BB4D CJVB
Start with Everything at "I OWN DOOM!" Skill	?GFM 7HYT BB9X KHVB
Start with Everything at "WATCH ME DIE!" Skill	?BF4 7HYS BB9D HHVB

Level Codes
On the Title Screen, click on the Options and from the Options, choose Password and then enter these codes:

Level 2 - The Terraformer	CQXK QBXT SY1? DSK7
Level 3 - Main Engineering	B9MG 2H9P 4KNH ZZ2Z
Level 4 - Holding Area	C?LB 6MN2 WTGF WJKB
Level 5 - Tech Center	CSP2 6NWZ ?8PF 6TKB
Level 6 - Alpha Quadrant	B96Z HSWT 3CTD FC?B
Level 7 - Research Lab	B5JD 4WB6 048W 2DKB
Level 8 - Final Outpost	F90C H111 XC4T XV9B
Level 9 - Even Simpler	FSSX H1WB ZDF? 6B1B
Level 10 - The Bleeding	D7F7 HDZT LFTD FR9B
Level 11 - Terror Core	NQ1K 691F ??CR PGGB
Level 12 - Altar of Pain	M99G HJY1 3FDN YRQB
Level 13 - Dark Citadel	4SNQ W3GW PPXY T9VB
Level 14 - Eye of the Storm	383S WGCS RC2P TLLB
Level 15 - Dark Entries	3RNL 4CC5 CVYP ?GLB
Level 16 - Blood Keep	29HC 4HH1 Y1TR PV3B
Level 17 - Watch Your Step	2QK4 6HMQ F7GR 42BB
Level 18 - Spawned Fear	1748 HSWL NC9? F4BB
Level 19 - The Spiral	1QFP Mb2N KZHM F73B
Level 20 - Breakdown	07VL HDX1 BCQR YDLB
Level 21 - Pitfalls	ORT? 4RD7 T4P9 K?BB
Level 22 - Burnt Offerings	Z9MG ?W79 64X4 873B
Level 23 - Unholy Temple	ZR67 ?H8G M1?Q ZPBB
Level 24 - No Escape	Y7Z3 071G CT74 JGVB
Level 25 - Cat And Mouse (Under "Features")	?TJL BDFW BFGV JVVB
Level 26 - Hardcore (Under "Features)	?TJL BDFW BFGV JVVB
Level 27 - Playground (Under "Features")	?TJL BDFW BFGV JVVB
Level 28 - The Absolution	W7JM OLX1 FRKR KMLB
Level 29 - Outpost Omega	RQ81 HNX6 7FOH 5??B
Level 30 - The Lair	V8C6 W3HL KPP4 1HBB
Level 31 - Into the Void	VRL5 6WQV H?WP LTVB