Rise of the Triad has close to a hundred cheats, and Apogee documented them in the ROTTHELP.DOC file shipped with the game. You simply type them during play. Each has a long and a short form — the short one begins with a backslash. You must first enable cheating with DIPSTICK, or nothing else responds.
Code (short form)Effect
DIPSTICK (\ECC)Turns cheating on and off — the other codes do nothing without it
SLACKER (\BUM)Three keys and health. The only one that works without cheats enabled
CHOJIN (\WWW)Woundless with weapons — invulnerability plus non-depleting ammo
TOOSAD (\GOD)God mode as a powerup
SIXTOYS (\GAI)All keys, armour and 100% health
GOTO (\GTL)Warp to a chosen level
GOOBERS (\GOO)Restarts the game at level one with only a pistol
CARTIER (\MAP)Reveals the whole map
RIDEMissilecam — the view rides the front of your projectile
FLYBOY (\MER)Mercury mode, i.e. flight
BADTRIP (\SHR)Shrooms — hallucination mode
BOING (\ELA)Elasto mode
SPEED (\RFA)Autorun
LONDON / NODNOLTurns fog on and off
PANIC (\PAN)Returns everything to normal
JOHNWOOTwo pistols
PLUGEMMP40
VANILLABazooka
HOTTIMESHeatseeker
SEEYAGod hand
Two things you will not find elsewhere. First, Apogee's own CHEATS.TXT contains typos — in the released source code the code table is stored backwards, and reversing it yields DIPSTICK (not "DISPSTICK") and PLUGEM (not "PLUGME"). Anyone copying from cheat sites inherits somebody else's typing mistakes. Second, the HOMERUN baseball bat code has the wrong length declared in the source, so the comparison never matches and the cheat is effectively dead.
In the shareware episode the vast majority of codes behave exactly as in the full game. Only five require the registered version: WOOF (dog mode), SPLIT, KESOFDEATH, HOMERUN and CUJO. In multiplayer Battle Mode cheats are disabled entirely.