tl;dr - Progress ruined, went through 'Door 16' only to fall through the ♥♥♥♥♥♥♥ floor down the hallway, no means of returning, in an 'out of bounds area'. Got stuck, 50 minutes down the drain. Very frustrating. Playtesters played this game, I saw them in the credits - yet something as horrible as an instant game-ruining bug such as 'Invisible Floor at one of the endings', just - somehow wasn't found before release?

For the developer on "Where?" - Its very shortly after the note of 'Go ahead and drop the unstable ones here'. I would immensely imagine that the invisible floor problem can be replicated.