A faithful interpretation, but a bit buggy.
I'm amazed that you made so many characters for the game, and not only pre-existing characters, but all the ones you thought ought to be in. Fits in very well with all the hype over what characters will appear in Smash Bros. Brawl. Each character has appearance, attacks, and sounds faithful to the original Smash, and there are plenty of levels and modes too.
The only problem I have is that the gameplay itself is somewhat lacking... it mostly comes down to spamming one or two attacks, and the AI tends to just run up to you. The percentage damage doesn't seem to affect how far you can be sent flying until you get above 150% or so, upon which any hit means an instant death. Feels very unsettling when some dinky hit that barely fazed you at 130% suddenly sends you flying off the screen at 150% in two frames.
But still, it'd be impossible to make a flash game that could compare to the original in actual gameplay, so I think this is an impressive flash and an achievement you should be proud of. Now I can play Smash without leaving my computer!