Only in Japan though, since the OST was exported in the oversea versions. The music it was changed to made it much duller.
Heero to the pilot of the Dark Gundam, Kyoji:
Heero: You're a psychopath! I will kill you!
Another from the second game: Amuro vs. Loran, simply for the fact that Amuro OVERPOWERS the Moonlight Butterfly with his mental strength.
In the second game, Judau Ashta, Amuro Ray, and Kamille Bidan's Big Damn Heroes appearance in Haman Karn's final story mode mission. Does it canonically makes sense? Not really. Does it rock anyway? Yes.
In Scirocco's ending in the first game Scirocco battles the Musha in a epic way, as well as cutting the Musha Gundam's arms off before it explodes.
In the english version you can do the same by putting Amuro into OO Raiser.
This Troper considers the voice acting for the english version of Garrod Ran from DW: G3 a CMOA for the writers and people who select the voice actors. The First time I selected Garrod Ran as a pilot, I cheered when I heard his brash arrogant over the top self introduction. But I really lost it when I first heard "Thanks for the Field, Suckers!" the first time.
In the opening cinematic, Turn-A vs Master Gundam. Master Gundam starts a Chouukyu Hao Den'ai Dan, but gets caught in the moonlight butterly, loosing an arm and wing. No sweat, the Master Gundam just keeps going, and kicks the Turn-A out of the colony they were fighting in!
Generally, any Pilot's finishing blow against the Musha Gundam in the first game, if it's done in cutscene.
Namely at the end of Kamille's story, where he charges at the Musha Gundam in the Waverider, with most of the other protagonists cheering him on, while firing shots of their own, distracting the Musha Gundam, allowing for Kamile to finish it.
At the end of Domon's story in the first game, Domon's stuck fighting Master Asia and (Probably despite how you were doing) Master Asia's thoroughly owning you. When it seems like all hope is lost, Rain, Milliardo and Puru start cheering Domon on, culminating in the four reciting Domon's "This hand of mine" speech!
The final mission in Kamille's story in the first game is full of awesome. It basically involves you and all the other Gundam protagonists facing off against their arch enemies in even combat. This lead up to Kamile facing off against Lieutenant Quattro, who's spouting his usual Breaking Speech where the protagonists give the obvious answer. This leads to the Musha Gundam battle and the awesome ending cutscene above.
The first "For Reform" mission in the the third game. Char and Haman are still fighting each other, and Mineva wants them to stop... so Banagher comes in with the Unicorn to kick both their asses, set to All For One.