I’ve discovered a subtle game-breaking bug (confirmed with the author) in Very Vile Fairy File. I’m pretty sure that this will be corrected in an update, but in case you’ve already started, save your game frequently and you can check here for a way to avoid it.
The bug and how to tell if you’ve hit it: After you’ve retrieved the cake cap from Lake Lap and returned in the boring boat, entering the boat should take you to a new location rather than Lake Lea. If it doesn’t take you to a new location, you’ve hit the bug.
The underlying issue: The code for taking you to the new location checks to see if you have the cake cap. If you have already retrieved it and gotten rid of it (the way of getting rid of it is a puzzle, which I will mention in the next hint), the game assumes you still have something to do in Lake Lea/Lake Lap and takes you there.
The puzzle solution you need to not do prematurely in order to avoid the bug: COUPLE CAPS with the cake cap and the other hats you can get.
So the way to avoid the bug is to retrieve the cake cap and then don’t do anything with it until you’ve already reused the Boring Boat. In particular, don’t do the thing in the previous spoiler.
Hope this is helpful!