Super Smash Bros. Melee

Hey how come MegaMan and Zero weren't in SSBM? they have been around since 8-bit nintendo and are almost as old as mario(well Mega Man is, Zero is slightly younger). that would have been great

Because they're not Nintendo or Hal characters. Nintendo owns the franchise, Hal develops it, therefore, trying to include any characters outside of either of those two groups' ownership would require massive royalty fees and a ton of red tape. Capcom owns Megaman and Zero.