Almost all Doom cheat codes will work on Doom Online, since it’s a port of the original shareware to the Flash format.
And here they go:
IDDQD - The God Mode (invulnerability) IDKFA - All weapons, Mega Armor (200% armor), ammo, and all keys IDFA - All weapons, Mega Armor (200% armor) and ammo, without the keys IDSPISPOPD - No clipping mode IDDT - Revealing the entire map in map mode IDBEHOLD - Gives power ups. Use like IDBEHOLD + S (berserker pack), V (temporary invulnerability), I (partial invisibility), R (anti radiation suit), A (automap computer) or L (light amplificator googles); IDMYPOS - Your position in HEX code IDCHOPPERS - Gives the chainsaw IDCLEV## - Warps to level E#M# (Doom & Ultimate Doom) or MAP## (Doom 2)
The following codes won’t work on the classic Doom and, thus, not in our Flash version:
IDCLIP - No clipping mode (Doom 2) IDMUS## - Plays music from level MAP## in Doom II and E#M# in The Ultimate Doom. This will will make the player change weapons in hand if the numbers pressed correspond to available weapons.
You can also watch the cheat codes in action in the video down below: