Not quite a masterpiece.
Alright, I have to applaud you for the large amount of coding done in this game, But thats about the only points you get. The rest is slapped together as well as a lackluster Gamemaker Creation, Creating it in Flash would probably be harder than Gamemaker, But my point is this is a better flash than it is a game.
Guiding Pikachu was like guiding an RC rocket, (his spinning headbutt unbalances the game as it can be done in mid-air and helps you scrape away from the edges of the screen when your life is low) Kirby/Metaknight confused me because each time I wasn't holding down an arrow key he was flying around the screen anyway everytime I accidently hit the attack button, (which is totally odd, considering Melee is a button mashing game and this time mashing worked to my disadvantage. I can't tell if thats a good or bad thing.) megaman's charge shot is seriously hard to aim mid-air because of the necessary charge time, so I ended up jumping and shooting and jumping and shooting when it came to the target stage, and I really have to mention how badly all the sprites are skewed and blurred. On a regular sprite you shouldn't be able to pick out individual pixels but on this game its the only thing you COULD do. Sometimes the sprites are bigger horizontally than vertically, sometimes the other way around, Point is its ugly.
Most of the game I just walked back and forth doing the same attack until my enemy flew off the screen at the speed of light, wash, rinse, repeat until I've finished off the Master Hand.
If its any console though, I'm 16, I understand flash and I'm a pretty Prolific spriter, And this game far outdoes anything I've ever made. Than again I've never tried either. Hah! Keep on rollin' em out dude.
-Senretsu
PS: 28 characters? Try a quality over quantity approach next time and see how that works out. X3