I'm not too upset about this video being all bout killing Yoshi's (to be honest, I never understood the obsessive fascination most people have with him. I find characters like Kirby, Pikachu and Isabelle to be cuter), but I say that no one should feel bad about watching this amazingly made animation because just the fact that you did all this in Mario Paint is so satisfying that nothing else that goes on in the video can take away from it.
This vid would have been HUGE had you released it years earlier. I could see this being an infamous meme. Though I will say that watching this now gives me a unique kind of fascination towards this and makes me think of why no one has thought about doing something like this in the years prior.
Personally, I would have liked to have seen Sonic be incorporated into this animation somehow. Mario and Sonic being in the same game together was unheard of back in 2000 and would have been awesome.
Regardless, this was superb. Would love to see you do more if you ever plan on creating anything else at this point.