I was trying to enter the walk through walls code when suddenly the weapon changed, turns out one of the control keys are in the code.

What da ya think?

Cheats? Pathetic. How could you need cheats!

I need cheats because I can't move on the second level.

GOD MODE

gozer - Will make you completely invulnerable to Enemy attack *WILL CAUSE SOME LEVELS NOT TO WORK PROPERLY*

WEAPONS CHEATS

egon - Gives you All Weapons, Keys and Full ammo *CAUTION, WILL GIVE YOU ECTO-1*

ray - Gives you All Weapons and Full ammo *CAUTION, WILL GIVE YOU ECTO-1*

NO CLIPPINGS

slimer - Allows you to pass through any walls, as if you were a ghost.

LEVEL WARP

warpmexx - Where the xx is a number between 01 & 32. type the appropriate number for the level you want to go to.

IDBEHOLD MENU

musakxx - Changes music where xx is a number between 01 & 32. Type number corresponding to level music.

pke - Gives your PKE Meter a boost, allowing you to see the Entire level.

goggles - Gives you a pair of Ecto Visors, that will light up an Entire Room.

tazer - Gives you a 200Volt Tazer, Quadrupling it's power.

winston - Gives you an Ecto Containment Suit, protectiong you from harmful slime.

peter - Makes you Transparent like a ghost, making it harder to be seen.

vigo - Turns you Temporarily into a Ghost, Also making you SEE like a ghost

I dunno why everyone wants to stress out. If you play with ZDoom, you can use the good ol' original Doom 2 cheats:

iddqd - God Mode
idkfa - All weapons + ammo
idclev ## - Jump to level ## (01-32)

I've been using Zdoom, that must be why they don't work, what is the doom cheat to walk through walls?

You shouldn't be using ZDoom. The levels are not the same as their supposed to be, as far as I know. But, if they are for you, keep doing it. Using GBD2 is better for gameplay as far as I know. Give it a try, and then use the codes…

JJ where do you enter the cheats?

Type “idclip” to activate ghost-mode, giving you the ability to walk through walls etc.
@Peter: Just enter the cheats while in the game, there's no special cheat screen.
@Spider: What do you mean by “Using GBD2 is better for gameplay”?
If you mean running GBD2.BAT, this file loads Ghostbusters Doom into ZDoom, the best Doom source port available. If you encounter any problems with ZDoom, I recommend using PrBoom instead, you can download it here. Doesn't have mouselook and many other features ZDoom has, but has a better compatibility and the cheats should work with it.
BTW, IMO the cheats don't work because ZDoom ignores them consciously when loading the DeHacked patch.

If you are using Zdoom enter the Doom 2 cheats. The game is still cool.