Super Mario Crossover, the pixel-for-pixel recreation of Super Mario Bros. that features a selectable cast of NES stars, was all set for the big 3.0 update this past June. It was unfortunately delayed a month, but it is now available for your pleasure. Head on down to developer Exploding Rabbit's site to give the new revision a spin.
New to 3.0 are the levels from Super Mario Bros. Special, a Japan-only port / remake for the NEC PC-8801 and Sharp X1; a difficulty system that drastically alters level layouts; and more skins for levels and characters to make them look like various other games on the NES, SNES, Game Boy, and so on. More tweaks and skins are planned for the future, but this is likely the last big update.
Exploding Rabbit is now hard at work on Super Retro Squad, which follows the style of Super Mario Crossover only with original characters and levels. While originally looking like an NES game, the graphics have been beefed up to a more detailed 16-bit style, though it looks like there may still be skins to "downgrade" the look to 8-bit and handheld styles. The game will also feature four-player online and local co-op. You can check the new screens below.
Super Mario Bros. Crossover 3.0 Released [Exploding Rabbit]