Haelian published a video a week or so ago setting out the probabilities for why it was so unlikely that this difficulty configuration would ever be beat: https://youtu.be/S-VUzcJHWF0
Which of course was taken as a challenge, with runner Jade clearing heat 64 yesterday, using an unseeded and unmodded run: https://youtu.be/0mo-kXjasZs
(For context, the seed is the way a particular run is generated, and players can meticulously generate seeded runs to ensure certain things do or don’t spawn by taking very specific sets of actions. Dying and respawning - rather then reloading from the menu, which is quicker - resets the seed. That’s why challenge runs always start with a death and respawn to show that a pre-configured seed isn’t being carried over from previous runs.)
Here’s Haelian’s reaction to the whole situation: https://youtu.be/5L7_3MrG_08
Insanely impressive, and I don’t know if we’ll get to see it again.
It’s important to understand that Angel1c (Jade) and Baj were the only two players with the skill level who could have possibly had a chance to beat unmodded, unseeded 64 heat. They already beat 64 heat runs with mods or seeds, so it was a matter of getting that insanely luck RNG to reach the goal.