There are some fantastic ideas in this set of levels. That crusher maze, for example, is a little frustrating initially but once you figure it out it's a really interesting timing puzzle that we just don't see in Doom.
By the way, in between uploading the previous level and this level, Romero released Sigil v1.1. Looking over the changelog, there's really two major changes; he changed some of the eye triggers to prevent soft-locks, and marked some items as multiplayer-only in the deathmatch parts of the levels so they don't prevent 100% item runs. Since I'm not going for 100% items and I would have to restart and re-record everything to use the new version, I'm continuing on with v1.0.
Doom: Sigil E5M4 - "Paths of Wretchedness"
Sigil is a new megawad by Doom co-creator John Romero to celebrate Doom's 25th anniversary, taking its place alongside the original Ultimate Doom episodes as episode 5. It features nine brand new single-player/coop levels and nine deathmatch levels. I'm playing Sigil v1.0 (v1.1 is released at the time of uploading) on Ultra-Violence difficulty on the GZDoom source port.
There are 216 views in 8 videos for Sigil. There's close to an hours worth of content for Sigil published on his channel, making up less than 0.51% of the total overall content on Ghastly, the Tinkerer's YouTube channel.