lothe

Is there a way to make one-way pipes in SMM?

I'm trying to recreate Super Mario Bros. world 1-1 in SMM, just as an exercise, and when you exit the subworld, you pop out of a pipe near the end of the level. In the original game, you cannot re-enter this pipe (or enter it at all), but so far in my SMM version, the player can enter the exit pipe.

I created the subworld with the entrance pipe (Mario simply dropping from the ceiling, rather than out of a pipe, seems to be another effect SMM won't allow). I added a pipe to the subworld, and when the game prompted me to place an exit pipe in the main world, I did so. But I find this "exit pipe" is actually two-way.

I've seen player-created levels that seem to have one-way pipes in them, so there seems to be a way to do it. What am I missing?