Vs. Super Mario Bros., is nearly a separate game in its own right. This game, one of several made for Nintendo's NES-based arcade cabinet, the Nintendo Vs. Unisystem (and its variant, Nintendo Vs. Dualsystem), is based on Super Mario Bros., and has an identical format. This game is harder than the original Super Mario Bros., with fewer warp zones and power-ups, and more enemies. The stages are different; the early stages are subtly different, with small differences like the omission of 1-up mushrooms and other hidden items, narrower platforms and more dangerous enemies, but six later stages are changed entirely. Many of these later, changed stages reappeared in the 1986 game, Super Mario Bros. 2 (Japan).
The plot is the same as the original Super Mario Bros., featuring Mario (or Luigi) setting out on a quest to free Princess Toadstool from the evil Bowser and restore the fallen kingdom of the Mushroom People.