Cheat mode:
Enter one of the codes:

Result - Code:

All guns - rdguns
Full inventory - rdinventory
All keys - rdkeys
Toggle debug mode - rddebug
Motorcycle - rdjoseph
Increase damage - rdmrbill
Suicide - rdrhett
Mushroom mode - rdaaron
Toggle God mode - rdhounddog or rdelvis
All guns, ammo, items, keys - rdall
Toggle coordinates - rdyerat
Toggle use of [F7] for view mode - rdview
Toggle lock - rdunlock
All items - rditems or rdmikael
View frame rate - rdrate
Set skill level - rdskill(skill level)
"You Were All Wrong!" message - rdteachers
Moonshine - rdmoonshine
Toggle monster respawning - rdcritters
"For You Grandpa!" - rdrafael
Toggle full map - rdshowmap
Toggle clip mode - rdclip
Disable all cheats - rdnocheat
Toggle drunk mode - rdwoleslagle
Boat - rdgreg, rddonut, or rdarijit
Toggle alternate debug display - rdnoah
Chicken mode - rdkfc
Mark opened doors with feathers - rdcluck
Shrinking opponents - rdtony
Larger opponents - rdvan
Slower game - rdtime
Turn into a chicken - rdgary