Co-Op Event 21: The True All-Star Battle

Pikachu
Pikachu is THE character to use! Both players should use Pikachu. One should stand on the top platform and repeatedly use Thunder while the other stands on the main platform directly underneath. The bottom player should also use Thunder, but keep an eye out for CDs, stickers, Smash Balls, and other important items. Since all of the enemies will fall from the top, Thunder will be extremely effective and will almost always KO the opponent. This includes heavy characters like Bowser. If anyone manages to slip past, the bottom player should deal with them.

Use defense. Pit's Angel Ring and Fox's Reflector work easily. Or just use Snake's up smash under the middle platform or Pikachu's down B on the middle platform.

Make both players Kirby and keep using his down-B in the air.

Ike
Use Ike's Up tilt constantly to hit all characters that fall from the top. It will kill them every single time. You can do this without taking any damage or using any stock.

Lucas
Keep using his up smash. You will win.