When Nintendo originally started doing tests for Super Mario 64, they had an idea of having both Mario and Luigi getting in on the fun. As fans know all too well, that ended up not being possible. It's not for a lack of trying, though.
In an interview with the Guardian, Shigeru Miyamoto details why Luigi didn't make the cut for Mario's debut 3D adventure.
“When we tried running our experiments with 3D on a console, Mario was the only thing that moved. Of course there was no background, either. While we’d expected things to be limited, what we ended up with was even less than we anticipated. It was at that point that we gave up on having Mario and Luigi appear at the same time and decided instead to rework the gameplay.”
While fans might remember the lack of Luigi as a sore point, one standout moment for Super Mario 64 was the title screen. Not only did it introduce the world to 3D Mario, it also let players manipulate Mario in a way we'd never seen. Nintendo's Takashi Tezuka explained how that came to be.
“I wasn’t involved in the game design for Super Mario 64, but because it was 3D there were lots of things we were dealing with for the first time. While we were struggling with that, Mr Miyamoto said that he wanted to make it so that players could play outside of the game itself with the model of Mario’s head that a programmer made; letting them rotate it, or pull its nose.”