The original plan for Super Mario Bros. was for video game's biggest hero to shoot enemies with bullets rather than toss fireballs at them, according to Mario's creator.
As part of a 25th anniversary celebration of the Nintendo classic, legendary Nintendo designer and Super Mario Bros. lead creator Shigeru Miyamoto explained the change in Mario projectile violence in an interview with Japanese gaming magazine Famitsu. The answer was translated by 1up.com:
"During much of development, the controls were A for shoot bullets, B to dash, and up on the control pad to jump," said Miyamoto. "The bullets wound up becoming fireballs later — we originally thought about having a shoot-'em-up stage where Mario jumps on a cloud and shoots at enemies, but we dropped it because we wanted to focus on jumping action. The sky-based bonus stages are the remnants of that idea, you could say. In the end, we realized that being able to shoot all the fireballs you want while running gave Mario too much of an advantage, so instead we had it so you shoot only one fireball when you start running. That freed up the A button, and we made that the jump button. I really wanted to have A be the action button and make you press up to jump, but it definitely worked out better for Mario in the end."
But why does Mario jump on turtles? Find out that and more at the full post. Great stuff here, as part of the 25th anniversary celebration of Super Mario Bros.