In January, during the run up to the release of DOOM (the 2016 one) the game's original designer John Romero released a new level for DOOM (the 1993 one). Now we get to see what went into it.
If you're after some more classic PC games from bygone eras, look no further.
E1M8b, a remake of the original E1M8 designed by his co-developer at id Software Sandy Petersen, features some insanely fiendish tricks of the game design trade, which is par for the course for classic DOOM really.
Romero shows us nested secrets, spawn triggers at the optimally inopportune moments and other dastardly deeds he put into the remake.
The walkthrough appears to have been recorded some time ago, though at least it finally made it to the light of day when Romero tweeted it out in the early hours of this morning.