Er. I tore up the notes and got the option now but both walkthroughs explicitly say not to do that so I guess I'll see how I go.
EDIT: Turns out I accidentally activated the Papyrus flags, I guess.
EDIT 2: NOW I'm stuck at "You go down the stone steps." Itch won't let me put an image here but the box is tiny and all I can see is the box, those words, and the back arrow.
EDIT 3: I restarted the game from the beginning trying to limit how much I loaded saves or pressed the back button and didn't get stuck this time. I got stuck at the "grim reaper" monster instead, the exact same way as I did at the steps, and couldn't follow the walkthrough for that part, so hopefully that's not...too important? I saved around that spot so it should be fine to try again later. I should add, I got this same problem in the Horrortale and Slumbertale IFs. But not once did I get it in the one for Underfell, and I haven't tried Mafiafell yet. Also, I'm using Firefox, and I tried switching to Chrome for a second but the problem still happened - so it's not likely to be a browser issue.