In Star Force 2 there's one, where Geo has just been defeated by Rogue and looks like he's about to be destroyed and the OOpart taken, then in a flash of light hits and who comes to save him in Big Damn Heroes fashion... Harp Note. This is after she supposedly joined the bad guys.
Star Force 3 basically took the plot from the final chapter of Battle Network 4 and extrapolated it into an Evil Plan worth acknowledging. Some respect for the writers is due.
One for the villains in Star Force 3: The first few scenarios are pretty light-hearted and more or less typical early game fare, until you beat Club Strong and Joker appears for the first time. There's barely time to react before he utterly dominates the heroes, nearly kills Luna and whiplashes the plot so hard it's a miracle it doesn't just break in two.
The attack on WAZA in Starforce 3. Dealer sieges the base with hundreds of Omega-Xis copies. Harp Note looks like she's finished when suddenly, out of nowhere, in comes Omega-Xis.
And then there's what happens right after, really showing just how much of a Hope Bringer Geo is. He immediately rallies the elites of Project Transcode to guard WAZA's core (including calming down his hotheaded friend Bud). Then with naught but the help of six Red Shirt wizards, defends WAZA from the onslaught of clones. The game switches to a minigame where you command Omega-Xis to slash the crap out of anyone in your way, and it is AWESOME.
Another moment is when the school is trapped inside Noise Space. Geo tries to find his way out when he sees that Solo is also trapped with them. Seeing that he has no other options and a wave of giant Noise Viruses are coming their way, Rogue decides to fight together with Megaman, complete with a minigame where you shoot down viruses to free up space for Rogue to slash the crap out of the boss, and its very own Awesome Music.
In fact Star Force 3 is just full of awesome moments, such as Ace and his Dying Moment of Awesome when he takes in The Corruption and sacrifices himself to save everyone from the noise.
What fails to be remembered a lot is how Joker has been forced to detonate against his will. He's having the psychotic breakdown of a lifetime, and then Ace steps up to bat. Joker actually starts encouraging him as he laughs.
Heartless wrenching control of Meteor G away from King. As she does so she points out how utterly misled he was; not one of his subjects ever granted him any value as leader — even Joker was in his employ only so he could do what he felt like.
King wrenching it back by becoming an EM Being. And then fusing with the Crimson Dragon.
Tia and Jack are defeated inside Meteor G and after they decide to stop their desire to destroy the world, both Virgo and Corvus don't like the idea and instantly try to kill them. Cue a epic Big Damn Heroes moment by Rogue who came out of nowhere to kill both Virgo and Corvus.
The post-game has Geo flaunt his credentials. At this point, Geo's already saved his world three times, with a technical fourth if you add the Bad Future from the second game. The post game has Geo go STRAIGHT TO THE CENTER OF THE GALAXY to save planet FM by beating the physical embodiment of a black hole. This Kid Hero is one HELL of a warrior.
Note that even the three Sages from Planet AM are unable to do anything about the threat but hold it back. Cepheus and the Sages all acknowledge Geo as their hero, and their great friend.
Lyra Note's debut as Mega Man's partner has her playing some rock and roll (the Theme Song in Japan). While she doesn't do much more than convince Gemini Spark it's not worth their time to deal with her, too, she basically managed to save Geo's life by giving herself a theme song.
Also part of Gemini Spark's debut, Geo deciding to run off and fight Gemini with or without Mega's help.
On that note, Gemini Spark's debut, for Gemini. He basically spends fifteen minutes making it clear that Rockman is completely outclassed against him. Even when Geo starts using his brain and manages to split the two Sparks apart, he still loses against Black. Even Mega admitted at the end that this was their complete defeat.
Crown Thunder gets a little bit Crazy Awesome in his debut; he surfs around on a set of Roller Coaster cars as he fights.
Cygnus Wing returning, and proving he's not here to mess around. He unites all the FM-ians save Gemini under his own leadership and actually gets his hands on the Andromeda Key for a few glorious moments.
He was pretty damn good in his first appearance, too. Most FM-ians would cause some mild chaos when they showed up. Cygnus Wing's plan was to hit AMAKEN with a satellite!
Rock Man totally wiping the floor with all of the FM-ians when he first gains the Star Force.
Goyouda, who hangs out near the bottom of the series' Super Weight, regularly entering battle with superhuman foes, including the viruses, the virus-man, the FM-ians, and the UMAs, not to mention Andromeda. He insists his subordinates show the same dedication.
Don't be an idiot! The patrol light on my head called us here to defeat this evil!
The Satellite Admin'sHeroic Sacrifice against Andromeda. They manage to destroy both arms and leave it just weak enough for Subaru to finish it off with the Break Sabre.
Tsukasa shows us he knows how to go Jumping Off the Slippery Slope by murdering Gemini to fill up the last bit of the Andromeda Key. And still in Super form, he makes off with the Andromeda Key, Laughing Madly the whole time. He also demonstrates he's not stupid enough to pick a fight, instead sending Rockman racing back down to the planet to catch the Andromeda Key after he ditches it. As Andromeda is about to destroy it. Rockman just barely catches it.
And then he has the biggest Oh, Crap! in the series when he sees the green light catching up to him. This is totally justified, since, when it does hit him, it rips him apart.
An impressive number crop up in the Season Finale of the Tribe anime.
Burai, near death, showing up basically to reaffirm that he wants Orihime and her crew to GTFO. He ends up in a fight with Hollow, which has them both frequency-jumping and fighting at the same time.
Goyouda, totally out of his Super Weight, as always, climbing down to try and retrieve the Sword of Berserk from its pedestal.
I don't care if it's Ra Mu or ramen... Goyouda will never let it be revived!
Harp Note saving him from being suffocated by Phantom Black... and then Cancer Bubble saving her by Tidal Waving Phantom Black and Yeti Blizzard before they've had the opportunity to do much more than look threatening. And then he and Harp Note bicker about his sense of priorities.
Harp Note: What's more important? Sorting receipts or the fate of the earth?!
Cancer Bubble: But I'm an FM-ian...
Harp Note: No buts! You'd die too, if this world disappears!
YB and PB are both washed away. Orihime just summons a barrier out of nowhere, totally unflappable.
Subaru has to run what is effectively several miles of stairway to get to the throne room, and then he dives headlong into the the lake at Ra Mu's base to rescue War Rock.
Goyouda taking a pot shot at Hollow. It doesn't do anything worse than get his attention, but that's enough.
Tribe King Rockman taking everything Hollow has without doing so much as adjusting his balance, and then dispersing Hollow's Lightning Bazooka with a wave of his sword.
Luna, Gonta, and Kizamaro back on Earth are surrounded by viruses and still fighting. Luna gets some small Character Development, too.