A little over a year ago, I posted the video of someone finally beating the hardest Doom map ever in a single shot (#456860). That was on the easiest setting, though.
A year later, the same streamer (Coincident) pulled it off on UV-Max (which means using Ultra-Violence -- the hardest normal setting -- and scoring every single kill).
Again, a huge video (can't imagine anyone really watching it in one burst), but also an amazing example of Doom talent.
This is just one step away from complete madness. Something like this inevitably re-wires parts of your brain and the person should be studied over time...
I legit feel like watching his channel is basically helping create that study. He notes in the comments that he's put over 2000 hours into this map.