The official Cheats page

[DOSGuy]

This is the place to post cheat codes for inclusion on the site.

Cheats must be verifiable by being possible on a version that appears on the site or, if from a version not on the site, documented by a reliable source.

[leilei]

THE DOOM CHATES!!! written and TOTALLY RESARCHED BY ME

idkfa = gives all weapons and keys and ammo
idfa = gives all weapons and ammo
iddqd = Degreelessness mode aka GOD MODE
idspispopd = no clipping (Doom)
idclip = no clipping (Doom II)
idchoppers = gives you a chainsaw that "...doesn't suck"
idclev!# = Changes level, the ! indicates episode number, the # indicates level number
iddt = Map detail
f10-y = enables the sexy version. now you know why doom is so super popular!

[MrFlibble]

Quite recently I've learned that the cheat codes in the demo of Hexen: Beyond Heretic are different from the cheat codes in the full game. The demo cheats are, essentially, the names and initials of the developers, as listed in the help/ordering info screens. The full list of cheats can be found here (for some reason the demo version is called "shareware" on the wiki, which is incorrect).

[MrFlibble]

A user in another forum was asking for Robomaze III cheats (power codes), and a brief search found this:

Hints and Tips

To progress faster in the game use the power mode.

~*H -- for double hearts
~*M -- for double money
~*D -- for double firepower

Each code must be entered separately, and the letters must be pressed while
holding down the shift key.

The source turned out to be actually the shareware readme file, which I found here. I'm not sure though if the codes are the same for The Dome and The Final Journey.

[DOSGuy]

Interesting. The version on the site has the following text at that portion of tellyou.doc:

To receive the secret codes to activate the power mode, which gives you double hearts, double money, and double firepower, send a self-addressed, stamped envelope to MVP Software. Or just register the game!

The top of the file in my version says "13960", versus "14081" in the version you found. Either it comes from a registered copy of the game, or it was added to a later version of the shareware distribution.

I tried those codes in Hoosier City on a hunch, but they didn't work.

[MrFlibble]

Hexen: Beyond Heretic

mraymondjudy	all keys
tmoore	all quest artifacts
braffel	all standard artifacts
crhinehart	all weapons, full armor and full mana
plipo<0-2>	changes character class
sgurno	full health
bgokey	god mode
cstika	kills all monsters on level
bpelletier<00-04>	level warp
rambo	lose all weapons
rjohnson	no clipping mode
init	reload level
mwagabaza##	run script ##
jsumwalt	shows coordinates
rrettenmund	shows ticker dots for FPS
pmacarther	shows version information
schilder	sound debug data
reveal	toggles map mode
ebiessman	toggles temporary pig mode
quicken	type it 3 times for instant death

Source: Hexen: Beyond Heretic Cheats, Codes, and Secrets for PC - GameFAQs

[MrFlibble]

Descent

GABBAGABBAHEY	Cheats enabled!
SCOURGE	WowieZowie Weapons!
MITZI	All Keys!
RACERX	Invulnerability On/Off!
GUILE	Cloak On/Off!
TWILIGHT	Shields Recharged!
FARMERJOE	Warp to Which Level?

Source: Descent Cheat Codes (Wayback Machine copy of Interplay website)

NOTE: These are only the shareware-compatible cheat codes.

Descent II

GABBAGABBAHEY	Lose all but 1% of shields and energy
ZINGERMANS	Invulnerability toggle
MOTHERLODE	Wowie Zowie Weapons
ALIFALAFEL	Accessories
EATANGELOS	Homing Weapons (every weapon will home)
CURRYGOAT	All Keys
WHAMMAZOOM	Level Warp
ERICAANNE	Bouncing Weapons
JOSHUAAKIRA	Full Map
BITTERSWEET	Psychedelic walls
PIGFARMER	Use it once and it displays "Hi John!!!" Now reduce the size of your screen Use it twice and it displays "Bye John"

Source: Descent II Cheat Codes (Wayback Machine copy of Interplay website)

NOTE: These are only the demo version cheat codes.

[DOSGuy]

All of the above cheat codes have been added to the site.

[MrFlibble]

Cool, thanks!