This would have been a 10, but...
The controls, man "o" and "p" for jumpin and attacking, hurt my hands when the buttons are so close to the arrow keys. Next time, use "a" "s" "d" "z" "x" or "c" for those buttons for 1st player, and It will work. (do it, and don't worry about multiplayer on one computer, I doubt that anyone will have 2 people on one PC or MAC)
Here is why I chose those numbers-
Graphics 10- Sprites, but it's an game, so it's ok.
Style 10- SSB flash game, an first (well for me anyways)
Sounds 10- Classic VG music
Violence 2- It's an fighting game.
Interactivity 5- due to the Controls.
Humor 7- Sonic and Megaman beating up Pikachu... Classic
Overall 8- Fix the Controls and add online (multiplayer online) to it, then it will be 10+ flash game.
Can wait for Super Smash Bros. Brawl.