Hey there, just to confirm, I submitted two different .zip files to the game jam, one of which was called "GMTK - Escape The Loop_sound". I presume that you couldn't see it on your end?
Setting that aside though, I did actually attempt to dynamically adjust the wall speed depending on which section of the level you were navigating at the time (specifically, it would slow down when going through the more vertical segments since they required more time to get through). While during my personal tests I found that this system was working fine (for context, the game actually generates a new level layout every time you start a new game, which may or may not make your run easier), it's possible that I might've needed to take my own familiarity with the level structure more into account while fine-tuning the wall speed to make it easier for other players to escape from it.
Regarding giving the player some way to tell when the wall is coming, that is actually a good idea which hadn't crossed my mind, so thanks for bringing that to my attention! :)