The 'Super Mario Bros 2' We Got was a Substituion for the Real Sequel

Strange to not have known till now, but it seems the Super Mario Bros. 2 released in most places outside of Japan was actually a slightly reworked version of a game called Doki Doki Panic. The real sequel was deemed too difficult; though a modified version of it was later released here as 'The Lost Levels' on the Super Mario All-Stars game on the SNES.