It took them quite a while, but finally, in 2011, ↑John Romero and ↑Tom Hall did a post-mortem on ‘↑Doom‘ (id Software 1993). You can watch the hour-long presentation, video and slides, ↑at the GDC Vault. If you do not readily understand everything the two guys are relating, I, for the umpteenth time, heartily recommend ↑David Kushner‘s ‘↑Masters of Doom‘ (2003). If you already have read the book, watch the post-mortem nevertheless.
For example, what I did not know: In March 1993 20th Century Fox offered id Software the Alien licence to make Alien the game. But the guys at id decided that they’d rather have the space marine confront demons and not merely an alien (around 00:22:00). So, the supernatural, occult dimension indeed was quite important to them.
ID SOFTWARE. 1993. Doom [computer game]. Mesquite et al.: id Software et al.
KUSHNER, DAVID. 2003. Masters of Doom: How two guys created an empire and transformed pop culture. New York: Random House.