Great game, but some problems.
I really enjoyed how you incorporated SSB into a 2d flash game. The overall feel of it was perfect, and if I didnt know any better, I would have figured I was playing Super Smash Bros. Melee.
The combat was simplistic and worked with the 2d sprite graphics. I really enjoyed playing it, and it is surely one of the best-made game on newgrounds today.
But it has it share of problems in my opinion. The one thing that bothered me was the movement. All the characters moved like they were on ice without skates. Combine that with "The Race to the Finish" and you got a challenge, but not because of skill, but because of the physics. Another minor problem was the battle system in a whole.
Most of the time when I am around 80% damage I get hit, and a go flying like a pinball out of the screen. I see this as unfair, and it barely gives you a chance to even jump back onto the stage.
Thirdly, the animation with the moves looked nice, but there wasn't much variety between the characters.
But other than that, this is a great game and shows much promise. The game is so well done, that only a few problems get noticed.