Despite the name, this is a port of the first Super Mario Bros. and is based off the SNES port made for Super Mario All-Stars. The engine is remade, and as a result, the game is much more difficult to control. The bosses at the end of each world can now be jumped on like a standard enemy. Unlike bosses from Super Mario Bros. 3, the bosses die after only one stomp, which makes the battles fairly easy. It's also more glitchy than the original game, a prime example being the enemies glitching in certain situations. The graphics and music are taken from the original game, but the level intro/status screen is completely different and the music is slightly different here. Mario's small sprite seems to be an edit of his big sprite.
When Bowser is defeated for the last time, Peach can finally be saved although her sprites seem to be glitching indescribably. As you save the Princess, the text "THANK YOU SONIC THE KINGDOM IS SAVED NOW TRY AGAIN" is displayed.