It is said that the future is always born in pain. The history of war is the history of pain. If we are wise, what is born of that pain matures into the promise of a better world, because we learn that we can no longer afford the mistakes of the past.
Ass in Ambassador: G'Kar, the Narn Regime's representative to the Earth Alliance, who is more than willing to sell advanced weapons technology (stolen from the Centauri) to the humans to use against the Minbari, at vastly inflated prices, in hopes of falsely incriminating the Centauri Republic of supplying an enemy of the Minbari Federation.
His exact words were that "human currency has been devalued on the interstellar market." If you're on a losing war for the survival of your race/country/planet, your currency will be rendered worthless by others, requiring more to buy the same items. It's economic practicality on G'Kar's part. In fact in the series itself he and the Narn resistance have to buy the same weapons from a human arms dealer, and he remarks the asking price is far higher than what the Narn sold them for.
That said, he also agrees to broker a meeting between representatives from Earth and an important Minbari official to try and figure out how to stop the war. Depending on how you interpret his character, this could be anything from Jerk with a Heart of Gold to Even Evil Has Standards (he may have a hate-on for the Centauri, but that doesn't mean he likes the idea of the humans being slaughtered wholesale by the Minbari.) Or that he's simply an opportunist with a Long Game view on things, and figures having a human race grateful to the Narn for helping save them would be advantageous in the long run. The deal was actually brokered from the Minbari end, and had the fairly-obvious second message of "we know where the weapons are coming from."
Balance of Power: The primary motivation behind the Narns being willing to sell stolen Centauri weaponry to the Humans to use against the Minbari. If the Minbari track the weapons back to their creators, it will lead them to the Narns' enemies, thus ridding the Narn of the Centauri.
Subverted in the novelization, where the Minbari were perfectly aware of the Narn's plan, and simply didn't care one way or the other, their blood feud being only with the humans.
Be All My Sins Remembered: Londo's storytelling is interspersed with his regrets over all the hardship he was responsible for, including unintentionally prolonging the Earth-Minbari War, and being personally responsible for the widespread destruction on Centauri Prime.
Berserk Button: Hurt someone she cares for, Delenn will hurt you. Kill her mentor/father-figure, she will start a war to end your race.
Call Forward: Many, given that this is a prequel that is substantially a Clip Show of flashbacks from the original show.
Michael York has a blink-and-you'll-miss-it cameo as the weapons officer aboard the EAS Prometheus, the clip being recycled from A Late Delivery From Avalon, the episode he guest-starred in as a Shell-Shocked Veteran.
Michael O'Hare has a single scene towards the end of the film as Jeffrey Sinclair (originally The Captain on the show itself), leading a squadron of Starfuries at the Battle of the Line and being captured by the Minbari.
Clip Show: This film was produced, editing new footage in with footage used for flashbacks in the original series, in order to help familiarize new viewers with the show's universe when it jumped networks to TNT.
Curb-Stomp Battle: Almost every fight between the Minbari and the Humans. In one battle sequence, we see a sizable fleet of human ships wiped out in seconds.
Curb Stomp Cushion: The humans win a single battle against a Minbari cruiser, at the cost of most of the task force that ran into it. Otherwise, it is made clear that despite their horrific losses, the humans are making the Minbari pay in blood for every inch of territory they take.
Damage Control: After the Lexington's task force is hit by a Minbari attack, Sheridan begins reading off damage reports to the captain. When Captain Sterns fails to respond to his report, Sheridan turns around to find his superior has been killed, leaving him in command.
Despair Event Horizon: As the end of the war approaches, Earth is nearing this. Delenn also is nearing it as her ship prepares for the Battle of the Line. She is out of ideas, and her plea to the Vorlons is answered only with a cryptic response.
Disproportionate Retribution: In return for the death of their religious and political leader, Dukhat, the Minbari set out to wipe out all of humanity.
Do Not Go Gentle: As Londo narrates how hard the Humans fought back we are shown examples of it, including a Starfury chasing and shooting down a Minbari fighter just as two or three other Minbari were shooting at it from behind, a Nova-class dreadnought ramming a Minbari warcruiser in spite of being shot by the same warcruiser at least three times before the contact, and a unarmed human fighting a knife-wielding Minbari warrior, punching it after being downed and still trying to stand up and fight after being knifed in the heart.
Face Death with Dignity/Obi-Wan Moment: Londo's story to the children can be seen as both as he knows he will soon die and chooses to tell those who will come after him about one of his greatest failings so that they will not end up like him.
First Contact: A human recon expedition into Minbari space accidentally stumbles across a Minbari ship, and are spotted before they can withdraw. A series of misunderstandings leads directly to We Come in Peace — Shoot to Kill.
Five Second Foreshadowing: The Minbari realize their error in using the Warrior Caste's customary greeting towards strangers who might not react kindly to having guns pointed at them (particularly when their stealth technology prevents the humans from knowing whether or not the guns are running hot, and when their sensors accidentally knock out the humans' jump drives), immediately before the humans open fire on them in response.
Foregone Conclusion: Everyone who's watched the show knows how the war ends, but that doesn't make it seem any less tragic.
Hopeless War: For the humans. Londo assumes humanity knew this near the start of the war but that did not stop them from fighting. When other species might crumble with despair, the humans reforged their efforts and made the Minbari taste blood at every inch. There are plentiful examples on this page of just how hard Humanity fought against the odds.
The humans, I think, knew they were doomed. But where another race would surrender to despair, the humans fought back with even greater strength. They made the Minbari fight for every inch of space. In all my life, I have never seen anything like it; they would weep, they would pray, they would say goodbye to their loved ones... and then throw themselves, without fear or hesitation, at the very face of death itself. Never surrendering.
No one who saw them fighting against the inevitable could help but be moved to tears by their courage... their stubborn nobility. When they ran out of ships, they used guns. When they ran out of guns, they used... knives, and sticks, and bare hands. They were... magnificent.
I only hope that when it is my time that I may die with half as much dignity as I saw in their eyes in the end. They did this for two years. They never ran out of courage... but in the end, they ran out of time.
Hyperspeed Ambush: The Minbari have actually made it a standard tactic. They lure Earth warships into a predetermined position then jump right into the middle of them. The vortex itself is devastating to any ship caught near it, and then the Minbari proceed to carve up whatever's left.
Another happens when the Centauri interrupt the attempted peace meeting. They emerge from the jumpgate and destroy the Narn cruiser before it can identify them, then fires on the planet, killing the Minbari representative and ruining the only chance to end the war.
Hyperspeed Escape: Attempted by Captain Jankowski's scout expedition after they are spotted by the Minbari, but fails due to the Minbari's scanners inadvertently disrupting their jump engines.
Once they have disabled the Grey Council's starship and stopped the scanners, the human fleet proceeds to make good their escape. The Minbari proceed to follow them to their base and Kill 'em All.
Just a Stupid Accent: The French-accented Centauri nursemaid in the framing story stands out quite glaringly among every other Centauri we ever hear. In the Centauri Prime Trilogy, she is a major character and is described as having a "northern" accent.
Londo: I know my sins, and the price I will eventually pay for them.
Late-Arrival Spoiler: Chronologically, this show takes place before anything else in the series, but if you watch it first, it will spoil many important plot points throughout the first four seasons of the show proper.
Meaningful Name: The ship that makes first contact with the Minbari, starting the war that nearly wipes out humanity, is named for Prometheus, the Titan from Greek Mythology who stole fire from the Gods to give to man, and was punished severely for it.
Mundane Wish: When Londo tells Luc he may give any one order he pleases with the authority of the Emperor and asks him "What do you want?", Luc asks Londo to tell him a story. Londo ruefully notes that Luc's answer to that question was much better than his.
Londo describes going through this years later, when he learned that he was responsible for prolonging the war by ordering an attack on an attempted truce brokerage between the Earthers and the Minbari (brokered by the Narn), mistaking it for a weapons deal between the Earth Alliance and the Narn Regime.
In the novelization, Captain Jankowski commits suicide; the note he leaves behind simply reads, "On my head."note And the narration dryly notes the irony of this, considering that the Captain's choice in suicide method left little of his head to rest anything on.
Noodle Incident: The Omega Incident. A number of officers feel that Captain Jankowski was responsible for whatever went down there, but he was officially cleared of responsibility by the authorities.
Pragmatic Adaptation: The Soul Hunters were heavily involved in the beginning of the war in the show, a sighting of one their ships cluing Dukhat into the impending disaster just a moment too late and their subsequent boarding attempt to claim his soul being part of why emotions ran so high when the decision was made. They are neither shown or mentioned in the movie, which given they have no further bearing on events is probably wise.
JMS says that showing the Soul Hunters would have been too confusing to new viewers unless they took 15 minutes to set it up, which they couldn't fit in. They do appear in the novelization along with a scene in which a wall of Minbari try to prevent them from taking Dukhat's soul.
Rock Beats Laser: Human weapons and technology are far inferior to what the Minbari have. That said, nuclear weapons still prove to be quite effective once you manage to get the enemy close enough to the warhead to be caught in the blast. Sheridan does this by way of jury-rigged Space Mines in an Asteroid Thicket. Mind you, this is the only time in the war that any human commander wins a battle against the Minbari until the end of the war.
Space Mines: Sheridan mines the Asteroid Thicket around his crippled ship, using the ship's magazine of tactical nuclear warheads, before sending out a distress call. When the Black Star returns to finish off the surviving ship, Sheridan sets off the nukes.
Trust Password: After the attempt to end the war ends with a surprise attack, Lennon tells Sheridan something to say to his people. When they arrive they find Lennon's body and bring Sheridan, Franklin and G'Kar aboard. Sheridan tells them what is in Dukhat's sacred space (Isil'zha, the future), which prompts Delenn to let them go.