How the smurf they left out Gilgamesh is beyond me

Also... many of those were'nt "villains". Gary Oak is a "Rival", and predator only hunts creatures that are dangerous or armed, while Akuma only fights those who challenge him and who he considers worthy. And excuse me but Ridley > Mother brain. Personally i also think they should have not listed villains who were made famous through films/other media (like the predator and the joker). And did i miss Dr.Robotnik/eggman or was he absent too?