Port Used: GZDoom 4.11.3
Skill: Ultra Violence
There is, in fact, no way of knowing that the yellow key secret is there, barring pressing on every wall in every room and eventually getting lucky. Ugh.
Chapters:
00:00:00 Intro
00:00:14 E4M1: Cold and Stranded
00:11:21 E4M9: Maniac Mansion
00:43:20 E4M2: Hell Frozen Over
00:55:10 E4M3: Twilight Meat Train
01:09:48 E4M4: The Biospherians
01:31:58 Outro