1. Playing through all seven stages across the different continents.
2. Defeating all seven Dark Gaia titans in the various stages.
3. Facing and defeating the final boss, Dark Gaia in its final form.
Once you defeat the final boss, a cutscene plays out, showing Sonic returning to his normal form and celebrating his victory. This is followed by the end credits rolling, showcasing the game's developers and credits.
Keep in mind that completing the main story is just the beginning! Sonic Unleashed features various post-game content, such as:
* Additional missions and challenges
* Unlockable costumes and characters
* Collecting all the Red Star Rings
* Replaying the game with unlocked features and characters
Enjoy your post-game experience!