Mr. Game and Watch: Unlock All Chars. (After Mewtwo, Straight Away.) Optional: 1000 VS Matches.
Mewtwo: 20 Hours Multiplayer. Check in Melee Records. Optional: 800 VS Matches.
Just leave your Cube on Overnight while on an Unlimited melee. Wake Up, Reset, Fight Mewtwo, Beat Him, Fight GW, Beat Him. Easy.
Next Time you need help, use the Help Topic. Seriously.