Stage 5
Death Egg - vs. Zavok
(Remember to click on "Show more.")
If I recall correctly through the cutscenes, the search for Sonic wound up being something of a shaggy dog event, as Sonic was eventually removed from his cell anyway. Dr. Eggman decided the time was right, as he was on the verge of taking over the entire world, and he had Zavok release Sonic from his prison cell so Sonic could watch his friends get annihilated. Sonic, of course, is not going to have that, and he promptly gets into a fight with Zavok, the leader of the Deadly Six from Sonic Lost World. Zavok, in turn, brings in his giant Buzz Bomber and a swarm of regular-sized Buzz Bombers to fight Sonic with.
As this is still pretty early into the game, Zavok won't be putting up quite as much of a fight as he did in Sonic Lost World. The time requirement for this, at 135 seconds (2 minutes 15 seconds), is also pretty lenient, simply requiring you to know when Zavok opens himself up for attack and taking advantage of it each time. It is kind of annoying that you get these cutscenes sprinkled around all these stages with the timer still running up, but the time requirements DO have them in mind. (The timer freezes at the end of this though. The game isn't consistent about that, as some stages have the timer freeze at the end and some others don't.)
Unlike in Sonic Lost World, Zavok does no actual fighting of his own, letting the Buzz Bombers do the work. He will begin by summoning a group of Buzz Bombers that follow Sonic around, then a larger group of Buzz Bombers that will dive-bomb Sonic destroying themselves in the process. Finally, Zavok will pilot the big Buzz Bomber the slam down on the platform itself. If Sonic is on the platform (that is, not in mid-air), Zavok's crash will provide Sonic with the upward force needed for Sonic to automatically leap up to where Zavok is. Then use the Homing Attack three times--Zavok will block the first two.
After taking two hits, Zavok will change things up. First, he'll remove the outer perimeter of the platform, making it smaller. Now the Buzz Bombers are summoned at an endless rate, and Zavok will charge at Sonic along the platform itself. Eventually, he'll do the downward crash move again, allowing Sonic to hit him again.
Two more hits, and you're given a cutscene where Sonic knocks Zavok off the giant Buzz Bomber, depleting the rest of his HP and defeating him.
The time requirement here is 135 seconds (2 minutes 15 seconds), which is more than enough time. As long as you don't flub up any chances to hit Zavok, and they're all quite obvious, you'll clear the mission.
And look at that--they actually show the prisoners from inside the cells. Why they didn't do this for Stage 4 I don't know. I guess stuff like this is why people largely regard this game as rushed, as this is the kind of show-don't-tell that I can appreciate: If given more time, they could've done something like this for the rest of the game.
For the record, this is not the real Zavok, but a creation of the Phantom Ruby. Also, like any typical video game boss, the platform crumbles around him, forcing Sonic to quickly escape, which will constitute Stage 6, Egg Gate. What happens to the prisoners? I have no idea. Presumably, they are subsequently freed when Rookie and the others stop on by.
