Zero Master recently dropped a speedrun of Doom 2: Hell on Earth in 23 minutes and 3 seconds. The run is masterful and features a nice blend of map bugs and amazing shooting. I recommend you watch at least a few minutes of it.

From the video:

"This improves the previous record by Looper (30uv2325) set in Dec. 2010. by 22 seconds. Previous record before that was by Radek Pecka (30uv2609) set in Dec. 2003

So this is the second improvement in the last 10 years, though I don't think we will have to wait that long before we see the 23 minute mark broken.