A few things. Up needs to become jump, and O needs to be basic attack. Being limited to Captain Falcon's Falcon Punch variations is both restrictive and overppowering. They need a longer activation and cooldown. Turning O and P into W and E isn't a bad idea either.
I've only played C. Falcon and Megaman, but I can tell that Megaman is in desperate want of a melee attack.
Finally, in the Race to the Finish minigame those bee things shouldn't home in on you like that. They turn the level from a race into pinball.
Really great game. The controls are simple and intuitive, and the game itself is just pure fun. It would be nice if you could go for more than one year year (maybe an option to that effect, like going for one, three or five years). Overall, really great game.