What’s often missed is that everyone was puzzled about the goblins running in terror. Legolas having the face of sheer terror when Gandalf tells them of the Balrog also is great foreshadowing since Legolas is old enough to know that his kin fought firsthand these terrible beings.

"Foreshadow and Flame". The most effective foreshadowing.

the scene with Gandalf falling and cutting at the balrog as they fall mile after mile into the abyss is easily on of the most chilling and jaw dropping scenes in anything ever

Not to mention that after the "Run!", we don't actually see the balrog until the bridge, but just a dim light that just grows brighter and brighter to the confrontation.

I have believed for a long time, and still do, that the Bridge of Khazad Dum scene, is the greatest scene in the history of cinema. Like you said, from the moment Gandalf shouts "RUN", we are on a roller coaster. Each character is given a task, even small, to get through the stairs and across the bridge. They are attacked by Orcs from on high, so we get action, Gimli screams "NOT THE BEARD" so we get a laugh, and the several minutes after Gandalf's fall, twenty years later, rarely fails to get me to cry. And we see all the characters on the rocks of Dumril Dale display their emotions. Aragorn is torn and in shock when he sees Gandalf fall, but after he runs up the steps and out the gates, he changes. You are right, when Gandalf says "lead them" he means he is in charge now, and he has to put his sadness aside and focus on the mission at hand, as the king he needs to be.

Part of the credit has to go to the special effects people. The Balrog is truly terrifying in every way. Hats off to Peter Jackson's production team.

The scene when Gandalf tells them it’s a Balrog they’re facing has a “blink and you’ll miss it” bit. Legolas’ face is pure terror in his brief close-up. He’s the only one among the fellowship (other than  Gandalf) who would have heard first-hand tales of what these things were and what they were capable of. A Balrog would have been a campfire story to the rest of the team. Legolas, on the other hand, KNEW how serious shit just got..

You know there is great danger, when the guy who told off Elrond tells you to run

Just doing a LOTR re-watch. Frodo Chooses to go through the mines after Gandalf asks. "Let the ring bearer decide". Thus, Frodo's decision ultimately led to Gandalf's death. That's another layer that made that moment so much more impactful.

As a kid in middle school I remember reading fellowship and being excited that Gandalf was accompanying Frodo. He was a wizard, he was powerful, he was the rest of the fellowship's "divine" protection. When he fell to the Balrog it left a pit in my stomach, and I was actually angry that he was gone. My young brain understood that this was just the beginning of the grand adventure and already the strongest member of the fellowship that was meant to keep Frodo safe was gone. The feeling of safety was now gone from the narrative which only made me invest more of myself in the story and it's characters. If Gandalf could fall, so could anyone else.
Tolkien was masterful with his story telling, and Jackson captured it perfectly for the film

LOTR is a masterpiece of adaptation. In the books, Gandalf does not know what entity is present in Moria. Though he may have guessed its true nature, this is never confirmed until the Fellowship actually sees it. In the movies, it's somewhat more overt, but we have to remember that non-book-readers are the main audience, and they necessarily need more information to work with for the scene to make a similar impact. And even for book readers, the foreshadowing is effective. So, well done, screenwriters!

Holy moly.. I've watched this movie i don't know how many times, but somehow i never really realized that Frodo didn't know Gandalf was alive even until he destroyed the ring.. that's impressive indeed.

Gandalf saying "This foe is beyond any of you”"

Foreshadowing also happens before the Balrog when Gandalf tells Frodo that "some evil he has not yet been tested against."

6:32 As someone who watched the movies way before reading the books when we first see gandalf actually turn and comfront the balrog on the bridge i had the OMG reaction. It seems like gandalf is extremely outmatched and watching gandalf stand toe to toe with the balrog really cements galndalfs character from a viewing perspective. The confidence in which he speaks his famous line lets you know that really you dont understanding anything 100% gandalf the balrog or the universe that theres something greater happening here and ive always loved that about lord of the rings.

I love the analysis of Gandalf as the main character in the second act, and your use of the close ups really aids that argument. Kudos! I love it when someone can show me something new or provide a new perspective on these texts that I know and love so much!

The key for foreshadowing this climax is Sir Ian used his acting skills to portray the wizard for the duration of the film.

Not only was it one of the most epic scenes it gave birth to one of the greatest memes. Truly a masterpiece.

I think Tolkien himself would be very proud of how they handled The Fellowship of the Ring.  By far the best movie of the 3.

i know this doesn't relate to your point but i still love how a huge portion of the sound the balrog makes is a cinderblock being dragged along the ground. it just seems correct somehow given that it's not a modulated animal sound and feels more elemental-made flesh (but that just my take).