Antiyonder posted...
Both of them (Lost Levels and Super Mario USA) are basically officially produced equivalents to rom hacks.
Lost Levels (The Japanese SMB 2) being a remake of the first game, only much harder and World 9 being a shout out to the glitches version of levels.
Super Mario USA (America's SMB 2) being a reskin of another game.
And just both of them making Luigi more distinct than Mario, plus being single player.
Both of things have elements of truth to them, but are not really the whole story.
It's true that Nintendo decided not to localize their SMB2 because it was deemed too difficult for American players, but this was determined by having one American play test it. The guy worked in a warehouse. It also wasn't the only reason. Japanese players didn't respond entirely favorably to it because it was too similar to its predecessor. And personally, I found the original much harder.
On the second point, Doki Doki Panic was kind of an honorary Mario game anyway. It was made by the same people who made SMB1, according to the same design philosophies. To the point that they actively changed direction a number of times to keep it from being a straight clone. SMB2 also isn't a straight reskin. There are a number of differences beyond graphics, including the ability to run, shrinking when getting hit and the omission of a progress tracker that spammed all four characters' progress to unlock the true ending.