This is the most crystal clear explanation of the core gameplay mechanics/purpose of Sonic to date! He was designed that way since day 1 and people have a hard time realizing that. It's not about just "getting through" the game. The emeralds, time stones, good futures, fastest times, and more are what made Sonic re-playable in the first place. Sure just getting through to the end is enough for most people, but it happens a little faster with Sonic, because there is more to do than just beating that final boss!