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Particularly, after Shang tells Mulan to leave, she refuses to give up and passes the Secret Test of Character that had previously beaten everyone else in the camp.
And everyone cheers her on, and are inspired by her example to stop sucking at being soldiers.
Notably, Mulan really could have given up just then. In truth, the discharge was something of a godsend, because now her family had no obligation to sending a mandatory member to the army. It was over! Mulan had saved her father! The plot of the movie was wrapped up in one verse of song! But Mulan still didn't give up. She passed the test, and she did it not because her father would have been sent to war if she hadn't, she did it to prove that once, just once in her entire life, she didn't suck at something. And she did. She proved it to the whole camp.
Followed by her defeat of Shan Yu - in particular, facing him down with nothing but a paper fan against his sword and succeeding in disarming him - is a Moment Of Awesome not only for the character herself but for Disney's animated heroines as a whole.
Made even more awesome when you realize that the fan is one of the ultimate symbols of femininity!
The emperor, and subsequently all of China, bows to her. They don't just bow they Kowtow a sign of submission and deep respect.
This builds on a previous Moment of Awesome where the emperor shows Shan Yu just how much his military prowess is really worth: "No matter how the wind howls, the mountain cannot bow to it." OWNED.
Shan-Yu then tries to kill the Emperor in rage, and Shang blocks his blow just in the nick of time. Despite this all happening behind him, the Emperor calmly and indifferently walks out of the way as though he knew it was going to happen the whole time. Now that's composure.
He very well might have. Look at his eyes when he delivers his mountain line – he looks off to the side, as though he's noticing something while he's speaking. True, this means he might have heard help coming and that's why he said what he did, but it also means he wasn't even paying attention to the guy holding a sword at his throat. Holy balls of steel, Batman!
Mushu straps fireworks to his back in winged costume and launches himself in fiery red glory!
Guard: Who're you?
Mushu: Your worst nightmare!
Shan Yu's falcon/hawk/whatever takes a sword from Shang's hands, flies up with it, then lets go of it so that Shan Yu, standing in a shadow on a rooftop, can catch it. When Shan Yu catches the sword, he emerges from the shadow, grinning, and you can hear shocked gasps from the crowd below.
The sheer, complete shock that Mulan gives Shan Yu by simply tying up her hair: "The soldier from the mountains...!"
Chien Po pulling EVERYONE up including the horse!
In terms of animation quality, it's amazing in its own right that they were able to make Mulan look male while still retaining feminine qualities. The audience can recognize her instantly while still believing that the other soldiers thought she was male. To sell the 'pretending to be a man' concept, Mulan's facial design was altered slightly when she was dressed as a soldier, adding a few slight edges to what were just curved lines. It's not all that pronounced and easy to miss, but it works beautifully.
The entrance of the Hun army in the mountains. THAT is how you make an entrance; it was an "Oh, Crap" moment for all of China.
Related is the first twenty five seconds of the scene's musical score. You can just feel the army getting bigger and bigger, until they finally charge.
And then there's Shang's line when he and the soldiers draw their swords:
"Prepare to fight. If we die, we die with honor."
The soldier in the opening sequence. He knows that he's going to die, but he fights as hard as he can to use his last few seconds of life to set off the Great Wall's torch-warning-system (The purpose of the Great Wall, no one expected it to simply keep a determined military opponent out), and then stands up to the terrifying Shan Yu before his death. Thanks to him, Shan Yu fails. Without his warning, the Huns' entry into China wouldn't have been noticed, and the emperor would probably be dead because Mulan and company wouldn't have been around to save him. That guy is awesome, and he doesn't even get a name, but he still sets off the alarm-torch. When was the last time a Red Shirt was so awesome?
Says this while burning the nation's fucking flag.
After the guys have gotten the Emperor off the tower, only Mulan and Shang are left. Shang has been defeated by Shan Yu, so Mulan cuts the rope leading down to the ground. She has to know that this means they are almost certainly doomed, but it also means the Emperor is safe. It's even an in-universe moment of awesome for her, as the entire crowd erupts into cheers when she does it.