secret characters
Best Game Ever. Thanks goes to Xinn here on Newgrounds for posting this list as a review a while back. If it wasn't for him I would never have figured it out :)
Characters:
Luigi - Clear Adventure on at least normal with Mario.
Jigglypuff - Clear Adventure on any difficulty with any character.
Cloud - Complete 100-man melee with any character.
Crono - Clear 3-minute Melee.
Naruto - Clear Adventure with the original 13 characters.
Shadow - Clear Adventure with Sonic, Tails, and Knuckles.
Super Sonic - Clear Classic with Sonic on Very Hard Difficulty without getting Game Over.
Zero - Clear Adventure with Megaman on at least Normal Difficulty without getting a Game Over.
Young Link - Clear Classic with Link on any difficulty.
Inuyasha - Clear Adventure without losing any lives.
Mr. Game and Watch - Clear Target Test with every character but him.
Mr. Incredible - Clear Classic Mode with the original 13 characters.
Mewtwo - Clear Adventure with Pikachu and Jigglypuff.
Lloyd - Clear Adventure with any character after having one hour of total play time.
Blue - Clear Adventure with Blade on at least Normal difficulty.
P.S. I know how hard the 100 and 3 min. melees are so ill post a sort of cheat to help you guys out (i found this out by myself).
First, unlock Zero (shown above), it shouldnt be that hard.
Second, pick either the 100 or 3 min. melee (it works with both).
Third, choose Zero and when you enter the battlefield move under either the left or the right platform (works with both) and face toward the center of the stage.
Fourth, once under hold the up dierectional key and repeatedly press the attack button (there is no need to jump), he should do his regular up attack then do a spin move then repeat. This will make you virtually invincible, but if an enemy manages to hit you (excluding projectiles) you should move to a different area under the platform (you'll know your in the right place when the enemys behind you stand still just out of your reach but don't move as this could make them charge you).
NOTE: This "cheat" does require some endurance and patience as you will be pressing the attack key for a WHILE! But it is well worth it. Also I only tried this with Zero so experiment with other characters and see if you can find new ways to "cheat" ;)
P.S.S. I hope I helped some people out.