why is it that everyone is battling undyne the undying in the neutral glitchless, to what I remember. You don't fight her unless you're doing genocide.

The fastest route for neutral glitchless is to start out by doing genocide and aborting it after Undyne the Undying, because it puts Hotland in a state where you dont have to do any puzzles. It saves about 10 minutes.

With glitchless, you abort genocide at the last possible moment. When we spare Muffet it changes the run back to neutral. It also completely changes the Asgore fight since we are a much higher level.