Sonic the Hedgehog: The Movie (1996)

Sonic the Hedgehog and his sidekicks Tails and Knuckles the Echidna are determined to thwart a plan that would turn their Land of the Sky into the equivalent of The Land of Darkness, which lurks beneath the surface (and is obviously the former planet Earth). So they plow through to the center of the planet and the ancient city of Robotropolis (the former New York City?) to do righteous battle. The big question of the day is whether the usually evil Dr. Robotnik is telling the truth for once or sending the good guys into a trap.