The first of two final boss fights starts off with a bang. Sonic and Chip have just finished restoring the Chaos Emeralds, and things look like they're about to go back to normal... then Eggman shows up and wrecks the ground beneath them. Sonic the Werehog then starts the actual fight against the Egg Dragoon on a chunk of rock falling towards the molten mantle.
Right before the battle, Sonic the Werehog, in freefall, saves Chip, swings off of loose debris, grinds along the wall, and manages a Three Point Landing onto the remainder of the floor, all one-handed and in ten seconds. Too bad the werehog isn't always that agile.
The finisher (at least in the HD version) — Sonic jumps on the Egg Dragoon, has Eggman stab it with its own drill, punches the Egg Mobile out of its holders, then grabs it and just throws it away while the main body of the mech explodes. If that wasn't enough to repair the werehog's reputation, nothing is.
The Egg Dragoon battle might or might not be a homage to Olga Flow from Phantasy Star Online (just look up footage of both bosses). So does that make Olga Flow a crowning moment by extension?
Then right after that, Dark Gaia fully awakes and swats Eggman the hell away (no Enemy Mine required) and EATS the energies fueling the Werehog transformation, forcibly reverting Sonic to normal. Not to be outdone, Chip (who recently remembered his identity as Light Gaia) summons the seven Temples of Gaia to create a Humongous Mecha of his own — through sheer willpower!
And, at least in the PS3/360 Version, Chip gets his own CMOA. After he, in the Gaia Colossus, and Super Sonic reach Perfect Dark Gaia's shield, Chip forces his way inside it, with much effort on his part, to distract Dark Gaia as Super Sonic takes out the 'snakes' creating said shield.
This isn't mentioning the fact that after Super Sonic rescues him from Perfect Dark Gaia's grip, Dark Gaia goes all out and fires a huge beam at Chip. He sits there, holds the beam back until it gives out, winds up, and delivers the left haymaker of goddamn justice right to Dark Gaia's face. Dark Gaia is so stunned he doesn't even notice Super Sonic breaking the light barrier on an intercept course.
Don't forget the other Werehog fight. The first one, where he picks up a whole Phoenix and slams it down on the ground, howling triumphantly and smashing his fists together, was pretty awesome.
And let's not forget how 90% of the final battle against Perfect Dark Gaia is one tremendous NiGHTS homage. Seriously. 2D flying, paraloops, Gillwing's scream (just slightly higher-pitched) when you destroy the heads... this after the lackluster Journey of Dreams was almost enough to restore my faith in Sega.
The Wii/PS2 version of the fight is perhaps even more awesome, with Sonic orbiting around Perfect Dark Gaia while collecting rings and dodging claw swipes, then he charges at Perfect Dark Gaia's eyes and bashes them to pieces, dodging meteorites the whole way.
WHAT ABOUT EGGMAN!?! He faked a Wily surrender, and just when Sonic thinks he just defeated Eggman, Eggman uses a machine to suck all of the power out of Sonic, the best part being it was in Super form, and then, he finally builds Eggman Land, something he promised to do in, oh, I don't know, THE ENTIRE SERIES!?!
Sadly, everyone here has missed the true most awesome part of Unleashed. "Holy crap, it's Sonic! And he's actually going fast!"
Uh, hello? Eggman's role in the Unleashed intro was awesome, yes, but are we completely forgetting how awesome Sonic was as well? (Video here). Highlights include sliding underneath a robot, spinning around said robot, then plowing through more robots with his fist.
About the "first time" for Sonic getting forcibly depowered: technically, Knuckles was the first. Still awesome for Eggman, though.
The reveal that the reason Sonic's mind was unaffected by Dark Gaia's energy was that he was strong enough to resist it. To put things into perspective, the story takes place across many countries and you meet people who were possessed by Dark Gaia all over the world, and not a single one of them was able to resist it. Sonic's body was possessed by more Dark Gaia energy than anyone else, even being mutated by it, yet he managed to resist its influencewithout even trying.