Looking for something to scratch that nostalgia itch? How about Bubble Bobble in Super Mario Bros. This hack replaces most (not all) of the original SMB1 graphics with those from Bobble Bobble. On top of that, the palettes have been overhauled, and the gameplay changed rather dramatically.
In Super Bobble Bros, Bub cannot touch enemies at all, but can shoot bubbles forwards. Also, his jump is significantly higher than Mario's.
A massive thanks to Unsavory Maggot for taking the time to hack in 'Super Drunk', the Bowser replacement.
No-Intro Name: Super Mario Bros. (World)
(No-Intro version 20130731-235630)
File SHA-1: EA343F4E445A9050D4B4FBAC2C77D0693B1D0922
ROM SHA-1: FACEE9C577A5262DBE33AC4930BB0B58C8C037F7