As proof, I offer this Megaman Sprite History.
Megaman 1-6 (NES):
You can see the difference from one game to the next as they constantly iterated and revised. No resting on their laurels for these busy bees!
Megaman X 1-3 (SNES):
It's just amazing how they could keep on finding better ways to present their hero. There's no wonder why Megaman is such an enduring property for Capcom.
Seriously. Nine games, two sprites. That's probably a record.