This was really the first Mario game not developed by Shigeru Miyamoto. Instead it was done Gunpei Yokoi of Metroid fame and the creator of the Gameboy.
Despite looking like Mario got pooped out of the Atari 2600, it was generally the same as Super Mario Bros. Except the fireballs bounced like rubber balls, and the controls were a bit loose for a Mario game.
It had some pretty cool levels too, I even liked the switch to the shooter levels. Also marked the first time Princess Daisy appeared in the series, and her new look is nothing like her old pixelated zombie self.