Hey there, Flare! I have posted the fix on my blog (here), in the FAQ. But here's how to fix it:
I'm guessing you're on windows, if so, go to %appdata% and in it you'll find the file "RenPy"
Open the file and open SoUndisToxic, you'll find a "persistent" file. Delete it.
Then go to the game files (where you extracted it) and delete the persistent from the saves folder inside the game files.
That should reset the game completely (fresh start)
Endings will be locked again, but that's part of the story ^^
Hope that helps! :D