The current rules for this game say to start timing when you select new game and end after credits say "end." However, the time of Cacodemon's run as listed would therefore be over an hour (about 1:00:08 by my best effort). Instead the listed time is 55:48, which I can't understand - by every timing method I know of, I couldn't come up with that time. My best guess is that it was retimed with SDA rules (start at new game, end at final hit on Geist) but was then mistyped. That's just because I tried timing with those rules on my own and got 54:48, exactly one minute less than the listed time, and 6 seconds slower than Cacodemon's own timing method which was SDA rules but starting from first cutscene.
So - if I'm missing something I'm happy to be corrected, otherwise it seems to me that both Cacodemon's time on here and the rules should be amended to match modern timing conventions.
In the absence of Ghostscit, I made these changes myself. Again, if this looks wrong to anybody else then please let me know!
