How do i prevent players from skipping levels?

[tylernal]

On the world map you can just skip over levels and not do them. How can I make it so they have to complete the level before they can walk past them like in Super Mario Bros. 3?

[TheNewGuy]

Are you using the Legacy editor,PGE, or the smbx 1.4.4 editor?

[Taycamgame]

A problem I used to have like this one: When the first level was completed, all the levels would open.
The answer was simple: Make sure there are no paths behind the levels. If there are, then that path will connect all the paths it touches; in other words, all levels connected to that level would unlock instantly.
Just check by moving each of your levels slightly, and see if there are paths under them. If there are, delete those paths.