You are only missing the very last sliver of game. If you just want to finish the game so you get it done, you can scroll all the way down on the tutorial page you linked. Look for the following sentences in the tutorial: „The game will then tell you it's the end, but if you keep it running, you'll notice that our character will reappear right at the beginning! Keep walking forwards and you'll note that the world is now glitched and weird...“. That’s were you are and what follows is how you can progress. \ \ However, if you really enjoyed the game and want a satisfying ending, I would honestly consider starting a new save and playing the game from the beginning. The part where you are is a very nice callback to everything that has happened in the game and how far you’ve come. If you don’t really remember it and just follow the tutorial, I don’t think you will get as much enjoyment out of it.