how do you get to episode 4's secret level?

well... how?

in e4m2, when you teleport into the area with the bfg (telefragging the Cyberdemon) when you "use" the small lift in front of you, another lift activates near the blue door. You can't miss it.

but don't listen to me, I am incredibly stupid....

How do you get to episode 4's secret level?

LIKE THIS.

Do this simple procedure:
Type in IDCLEV49, and voila!
There you go. E4M9: Fear.
Umkay?

Heh, just look at everyone's custom titles...

Do this simple procedure:
Type in IDCLEV49, and voila!
There you go. E4M9: Fear.
Umkay?

Hmmmm, you could cheat too......

Do this simple procedure:
Type in IDCLEV49, and voila!
There you go. E4M9: Fear.
Umkay?

lol
Or idclip and switch the secret exit button...

Or use NWT and remove E1M1, then rename the E4M9 lump to E1M1, and start a new game on EP1.