I finished the level and i pressed save but every time i launch it, its just the old level and i cant play the on i made does anyone know what to do

Open NSMBe5, next open your rom, now go to tools/options, next go to NSMB Tools, then click multiplayer NARC Patch (Map) then click Multiplayer NARC Patch (Tex + BG)

tell me if this helped also you have to stick with the sprite sets that is in the multiplayer map but you can change the tilesets

I tried it and it just loads to a black screen

did you change the sprite sets?

no

About NSMBe not saving the level properly, I would try deleting and reinstalling the editor (make sure you export your level beforehand). If after testing it, the same issue occurs, then make sure you're using the newest version. I've downloaded this fork: https://github.com/MammaMiaTeam/NSMB-Editor/releases/tag/v5.4

Anyway, what do you mean by "You can't play the level"? Specify why exactly you can't, because it's too vague. Does the screen freeze and if so when does it etc. And maybe tell which emulator (or console?). Maybe it's not because of the level (there's a slight chance. What about the other roms, are they emulated correctly?)

If you're loading into a black screen that probably means you've added an object that doesn't work in MvsL. Check out this wiki page for a table of sprites that work.
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