Not how I'd tell a Smash Bros. story
Your work is good in some areas and really bad in others. Your story in the series is actually quite terrible. Sure, I'm a Nintendo fan too, but honestly, the story doesn't have much to watch on for.
I don't like the idea of the characters just knowing each other and act like they've been good mates for years. As you very well know that some of them have barely had any contact with each other. I think it should stay that way. However, it's far too late in the series to do anything about it.
Graphic effect wise, you're doing alright. Some of the effects are really good but not enough to bring your Flash up to scratch. Some of the sprite use is rather terrible, Master Hand's constant movement for one. Those who have played the game know that he slowly moves with the exception of attacking. The constant changing of sprites for characters isn't great either. Pick a sprite set and stick with it, only upgrading where applicable.
The sound is unbalanced, and I don't like having to have my hand near the volume control of my speaker. Some sounds are used too frequently and some don't fit in very well. Some of the music you include is perfect, others are far from perfect. There should be no breaks in the audio, unless they are scipted.
The damage meters you show when the characters battle the hands are stupid. If used correctly, maybe they'd be acceptable, but otherwise, they're distracting and inaccurate.
The dialogue is annoying because the story isn't made very well. On usual cercustances, I'd ask for voice acting, but I think it'd be of low quality and make the file size way too big.
Overall, I didn't enjoy it because of it's substancially low quality. If you fix all the things above in a seperate Smash Bros. series, I might watch it, but that was really bad and unexciting.