i can say ive played all the original games (minus the new ones that came out recently)
of all those games, i say that the best one ive played was megaman 8 the gameplay was excellent tough it also was the hardest......so many total gameovers, and not just from the sled levels
the only other levels that gave me total gameovers (tough only once each) were gutsman level in megaman 1 and plantman's level
now for the game that was the most fun was Power Battler 1, if only for wily's battle music. its simply bliss just listening to it --- Giovanni : hahaha Im the caid of my shoes and i control every toe-nail in it.