I got the "spinning" doors multiple times on the level 1-0, but it didn't lead to bowser, only to the space in the sky. So does it mean it doesn't work on 1-0 ? Does it work in 1-1 ? Only in 1-2 ? What are the conditions so that the spinning doors lead to Bowser ?

Stickied because this is essential to any%

So the faster method to get the any% would just be to wait in 1-0 and get the spinning doors and pray that the spinning doors "work". That's weird because I got the spinning doors in 1-0 quite a few times and it never worked.