Dunno if its been mentioned but kind of interesting that apparently a spectrograph analysis of the doom soundtrack shows the numbers 666 repeated in waveforms (mostly) outside human hearing range.
https://www.reddit.com/r/gaming/comments/4li77n/the_numbers_666_appear_in_dooms_soundtrack_in_a/
https://www.reddit.com/r/gaming/comments/4li77n/the_numbers_666_appear_in_dooms_soundtrack_in_a/

) and did nothing with it, so pretty sure that will come into play in the next game. I was expecting to fight that robot guy, didn't even know that spider was the last boss as it seemed too easy. I guess he will be the bad guy in the next game we will have to fight at the end.
