Doki Doki started out as a Mario game

[A Black Falcon]

That's pretty interesting... it started as a vertical-scrolling Mario concept? Huh. I assume the critics now will say something about how because Miyamoto didn't come up with the original idea it doesn't "count", or something like that, but it's interesting information to know. So it was Mario originally.

Also, too bad it didn't end up with co-op, it'd have been pretty cool to see.

And yeah, I've always liked Mario 2. Good game.