You did nothing wrong, it was an error on my side. I fixed it, but you'll have to download the game another time (or use itch.io app to update; but, as I didn't use Butler, I don't know if it will update). So, first thing go in the folder of your old game and copy your save files to another place, then download the new version of the game and see if it updates automatically with itch.io app. If not, open the folder of your new game version (the folder where you start the game) and copy/paste your saves into it. Replay "the sewers" from one of your saves before the door. Let me know if it works and sorry for the inconvenience!