Bundled with the Super Nintendo in December 1994, Super Mario All-Stars + World contains 16-bit enhanced remakes of Super Mario Bros, Super Mario Bros: Lost Levels (Japan's Super Mario Bros. 2), Super Mario 2 USA and Super Mario 3 as well as a slightly downgraded version of Super Mario World on the same cartridge. Due to processor and clock differences between the NES and SNES, the original NES game engines were not faithfully emulated, making slight changes noticeable to avid players of the original games.