Doom E1M8 in 17 seconds and Plutonia Map11 in 9 seconds with a rare glitch!

A few days ago I met with one of the people that inspired me to pick up doom speedrunning 8 years ago, which is Henning who did doom 2 nightmare in 29m39s back in 2009. He had a message from John Romero to me, you can see it here: https://vimeo.com/715249616/fe36cd0966

Unfortunately there's no doubt that the limit for E1M1 has been reached, so I won't be able to perform any magic there. However, there seems to be no end for things to be discovered in doom, so I have something else to offer which is a new trick for the only level in Knee-Deep in the Dead that John didn't design: E1M8: Phobos Anomaly, as well as a level in Final Doom.

Sometimes when you play doom there's a extremely rare occurence where you and the monsters can walk through walls, this is known as the all-ghosts effect.

Whenever someone encounter this glitch and wondered what happened, they always got the same answer: "An intercept overflow happened if you fired a hitscan weapon over 128 linedefs/things." And that's true, except never once when this occured for me were there even close to that many linedefs/things for 1 tracer, so it didnt't really give you the full explanation.

But thankfully a year ago decino decided to do an analysis on this glitch and gave the proper explanation for why this just happens randomly sometimes, which can found here: https://www.youtube.com/watch?v=-IYfwCWZeD0&t=410s (E1M8 footage is staged according to his comments in the video, so getting that to work normally is more complicated)

So with this knowledge in hand I figured one could almost do this just about anywhere really, this then leaves two candidates for this glitch to save time, which is Doom E1M8 and Plutonia Map 11.

For plutonia map11 there are 2 "exits", one of them is a normal exit that takes you to map 12 immediately, while the other teleports you to a room with 4 arch-viles and an E1M8 (sector 11) type exit floor. If you do manage to get an intercept overflow you cannot use the normal linedef exit or exit switches, but you can use the exit floor and it takes very little time to reach it from the start! We are also very fortunate to have 5 packs of shotgun shells stacked on top of each other on a table right at the very start which can be used to trigger this glitch reliably.

E1M8 only has one exit which everyone knows about: you kill the barons, go up the stairs and teleport into a room and die. However this level has 2 different tricks from before that allows you to get out of bounds. Since the exit sector extends beyond its boundary on the outside of the level you can exit without having to enter the room from the outside. But, if we could very quickly trigger the all-ghost effect then we could be even faster! We are not as lucky here though as with plutonia, but there are a lot of demons and barrels in the first room which we should be able to use somehow to still trigger it.

There are a few problems with this. First of all you'd need to find some spot where it actually works. Then once you've done that you need to get to this specific coordinate without spending too much time, or else you'd just be slower than the record. If you try to get it by random chance it would take an eternity, so that's not very effective.

So after several hours of brute force (having doomguy run around in the room shooting everywhere for many years in-game time) I managed to find some area where I'm able to get the intercept overflow. Afterwards I restrict myself to use various movement inputs that I'm able to easily do without TAS and then mostly brute force different angles that hopefully would lead me to a sequence of inputs that can perform this trick non-TAS.

And after many more hours I managed to find them, then it's all a matter of getting it correct in a demo, the results are what you see here. This improves the record for E1M8 by 2 seconds and Plutonia map11 by 39 seconds! Both of these demos play back in dosbox using doom.wad or plutonia.wad, so it's not a source port specific thing and the levels weren't edited to achieve this, though some source ports have a fix for this glitch preventing it from happening.

Thanks again to John Romero for the video message and decino for the analysis video he did a year ago on this trick.

Enjoy!

Видео Doom E1M8 in 17 seconds and Plutonia Map11 in 9 seconds with a rare glitch! канала Zero Master