Loved this, one of the best episodes in Quake's mapping history. The feel and aspiration of episode 4 is celebrated, amplified and reinvented here with a great deal of care and love. Inventive trap setups, insane geometry, ambushes, ambience and music, even dreaded spawns are well utilized here to create a brutal otherworldly dimension.
Diyu in particulars bursts with ambition. A huge non linear episode-in-itself, it is like an "open world" on Quake's terms, and expertly realized at that. I've found 14 keys but funnily enough now I think that I shouldn't have indulged myself and should have left earlier after carving my own unique path. Somehow, methodical exploration diminished an overwhelming, almost mythical feel this sprawling level has. But it may be just me.
Other highlights for me were the Family Tree, Arcana and the final arena in the penultimate level. I am conflicted on usage of particles to signpost the path through the level. Sometimes they are used well, like in Diyu to indicate that an area does (or doesn't) still have a key. But sometimes these particles feel like a crutch because the area design is too convoluted or consequences of button press are not obvious.
My complimets to music artists involved, the soundtrack is a perfect kind of dark, troubled ambient that enhances the episode's atmosphere.
Thanks, zigi and Newhouse, it was a joy to play!