Vectorman

In 2049, the human population of Earth embarks on a migratory voyage to try to colonize other planets.

They leave mechanical "orbots" to clean up the mess they made on Earth through littering and pollution.
Raster, a high-level orbot who watches Earth through a planetwide computer network, is accidentally attached to a working nuclear missile by a lesser orbot and goes insane, becoming an evil dictator named Warhead. He declares himself ruler of Earth, and begins preparing to execute any humans who dare return to their planet.