This patch allows you to hold the fireball shooting button down to keep shooting at a normal rate without having to release the button. Also, this patch makes Mario shoot two fireballs at once.
Super Mario Bros. (World).nes
CRC32: 3337EC46
MD5: 811B027EAF99C2DEF7B933C5208636DE
SHA-1: EA343F4E445A9050D4B4FBAC2C77D0693B1D0922