Final Doom - Thy Flesh Consumed - Against Thee Wickedly (E4M6) - All secrets

The barrier at the end is lifted once the cyberdemon is killed. I show how to get there, but since it's a run without monsters, I am unable to go past the barrier (unless I used IDCLIP, which I didn't this time).

This is played in GZDoom, but I only take routes that don't require jumping (even though I sometimes jump to speed up the walkthrough).