1. Complete the main story mode:
- This means finishing all the story missions for all the playable characters.
2. Collect all 180 Emeralds:
- This includes the standard Emeralds you collect throughout the game, as well as the special Chao Garden Emeralds.
3. Play through the game on Hero Mode:
- Hero Mode is unlocked after beating the main story mode.
4. Beat the final boss in Hero Mode:
- Once you've completed the game on Hero Mode, you'll be able to access the "Final Chase" stage.
Important Notes:
* You need to collect all 180 Emeralds even if you're playing on Hero Mode.
* You must beat the final boss on Hero Mode, not just complete the game.
By fulfilling these requirements, you'll unlock the "Final Chase" stage, where you'll face off against a powerful new enemy and experience a thrilling challenge.