Here is a hack for Super Mario Bros. which has all the level layouts changed. The levels were redone to give an added challenge to the game.
Super Mario Bros. (W) [!].nes - GOODNES 3.14
CRC32: 3337EC46
MD5: 811B027EAF99C2DEF7B933C5208636DE
SHA-1: EA343F4E445A9050D4B4FBAC2C77D0693B1D0922
SHA-256: F61548FDF1670CFFEFCC4F0B7BDCDD9EABA0C226E3B74F8666071496988248DE