This is an example of a bad hack. I did this because with more and more people suggesting to see runs of hacks made, I figured we ought to see a hack that proves that not all hacks are good. This is a hack of SMB1 that is the funniest I've ever seen. The game remains the same, save the princess from Bowser (or Koopa) and live happily ever after. The only thing changed is the sprites, which is why I only did the first level. I'm not going to reveal anything about the sprites because I don't want to spoil anything.
For some reason this hack would only work with Nesticle and Famtasia, so I chose the latter. You can get the run
http://impact.megarpg.net/TM.fmvhere and the hack <url to ROM removed by Bisqwit> here.
I think you will agree with me that while his hack is hilarious, it is a prime example of a bad hack.