Sonic Mania/Egg Reverie

The Heavy King (now the Phantom King) and Eggman's Klepto Mobile are in a tussle over the all-powerful Phantom Ruby, and it's up to Super Sonic to take them both out. While you can fly with a double jump, the safest strategy is to stay on the ground and wait for either Eggman or the Phantom King to fly toward you, giving you the opportunity to get a hit in against them. Between these attacks, you can collect some rings to avoid having your ring count fall too low; if it drops to zero, Sonic dies. Occasionally, the Phantom King will release some orbs of energy that do damage to Sonic. If you happen to get hit by one, go on the defensive and pick up rings until your ring count has recovered, in which case you can continue to attack. Get eight hits on each boss (sixteen in total) to defeat both bosses and obtain the secret true ending.

Congratulations on defeating the final bosses, and enjoy the special scene.