This is a classic hack done by Acmlm, the ROMhacker who founded Acmlm's ROM Hack Domain which is home to one of the most popular ROM hacking boards today.
This hack is complete and demonstrates what a quality hack should be. ALL of the levels in the game have been modified and most of the graphics have been overhauled and replaced.
This is the kind of hack that gets people interested in the hobby, so go download and try it out!
Note: A titlescreen patch fix is available separately
http://www.romhacking.net/hacks/559/.
Super Mario Bros. (JU) (PRG0) [!].nes
CRC32: 3337EC46
MD5: 811B027EAF99C2DEF7B933C5208636DE
SHA-1: EA343F4E445A9050D4B4FBAC2C77D0693B1D0922