The final battle against Darth Sidious in Lego Star Wars. Not only is this an awesome extension of Return of Jedi's final battle, but Luke fights him alongside Vader. Son and father have finally reunited and team up to take down the man responsible for both their pain.
Fighting Darth Maul with "Duel of the Fates" playing. Then playing AS Darth Maul. Freeplay allows you to play as Maul or Vader against the other!
The trailer for Batman 2: DC Superheroes even has one. After the words "Now the world's greatest heroes must unite to stop them" flash on the screen, a sudden cut to a familiar red-and-blue figure slowly descending from the sky... to John Williams' iconic Superman theme. And then immediately followed up by shots of the Dynamic Duo in action to Danny Elfman's Batman theme.
Flying with Superman is just all kinds of awesome, largely due to the music switching out to the aforementioned theme.
Even more once you realize that the hub is comparable in size to Arkham City, yet you can fly all over the place.
After a huge (and presumably directionless) chase scene through the streets of Gotham City, Batman reveals he's used the kryptonite leaking from Luthor's Humongous Mecha to create a giant glowing Joker face visible from orbit. Martian Manhunter gets the signal, and promptly calls in the entire Justice League.
In the movie adaptation, the fight between the League and the mech is pretty cool. Like Green Lantern creating a giant cage around it, or Flash removing all the kryptonite from its power core and loading it on Wonder Woman's invisible plane.
A minor one, but in LEGO Batman 2, when Batman is investigating Joker's escape, he tells Commissioner Gordon that he's heard rumors of Lex Luthor being "not-so-upstanding". While most people would say things like "that's crazy", Gordon just says Batman might want to tell someone. It shows Gordon knows Batman well enough to know he knows what he's talking about.
Batman scaring off a shark that Joker had sicced on him just by snarling at it is both awesome and hilarious.
Anytime you defeat an enemy as a Kryptonian while under the influence of kryptonite.
In Lego Lord of the Rings, despite being shot three times and only having one heart's worth of health, it's possible for Boromir to land the killing blow on Lurtz at Amon Hen.
The first mission takes place at the end of the War of the Last Alliance and the boss is Sauron.
LEGO Marvel itself looks like a CMOA for Tt Games. A gigantic NYC hub with just about every memorable character in the Marvel universe appearing!
The developers show that they actually do listen, and made a Big Fig version of Venom, whom Venom will be able transform into. Venom's transformation itself is composed of the Big Fig version of him tearing himself out of the smaller minifigure version of Venom.
That wasn't the first example. The entire inclusion of Gambit was because so many people wanted him in it.
Stan Lee: What does it mean to be a hero? It's more than just superpowers and costumes. It's being scared, but standing tall anyway. It's digging deeper, and pushing further than you ever thought you could, in the face of unthinkable evil. True heroes ban together to do what's right. Sometimes, it takes extraordinary circumstances to prove that maybe, just maybe, there's a hero in all of us.
Now that LEGO Marvel is finally here...
Doc Ock gets one for making a door by grabbing a helicopter right out of the air and swinging it into a building.
Magneto tearing off Iron Man's armor in seconds, then later controlling the Statue of Liberty like a puppet!
And then Mandarin actually manages to hold his own against them all! He's lost about half his health, but he's still fighting. Tony then responds by building a medium sized arc reactor from the scraps of his power suit army to fry the Hulkbuster. That whole boss fight is awesome, really.
Poor Thing just can't catch a break for the first few times he's playable and either his catch phrase is interrupted, cut short, or stolen. However, when he does finally get to use it when punching Dr. Doom off of the Asteroid M base and sending him careening back down to Earth, it is glorious!
The final boss battle against Galactus is just as epic and amazing as one would expect, with five steps, each with a different team composed of heroes and villains.
Three words: HULK THOR SMASH!
Don't forget the Power Walk that the heroes and villains do side by side.
Anytime you skydive off the Helicarrier. You get to the edge and jump. Then rock music kicks in, you hear the howling of the wind, and falling has never felt so cool.
Flying back up to the Helicarrier as either any flying character or in a plane is just as awesome. Especially if the flying character has a speed boost.
Jean Grey gets one for taking control of Juggernaut and wiping the floor with the Brotherhood mooks.
After beating the final boss, you unlock Galactus as a playable character, and it's just as cool as it sounds. He's understandably toned down to the size of a normal minifig, but being able to play as the guy you just beat the crap out of is just amazing on hundreds of levels.