- Advertised Extra: Despite being heavily featured in trailers and posters, Liam Neeson's character, General MacArthur isn't really the main character in the movie and just plays a side role.
- Anyone Can Die: By the end of the film, Jang Hak-Soo and all 7 members of X-Ray have been killed.
- Artistic License History:
- While there was indeed a special forces group sent to infiltrate Inchon, it wasn't made up solely of Koreans like the movie but a joint US-South Korean team made up from the US Military and the CIA.
- The mission itself also had a few details omitted; acquiring the plans and locations of the sea mines is prioritised as one of them, but also the defusal of said mines. In reality, the team reported that there was in fact an underwhelming amount of dangerous sea mines placed in the channel making the mission easier than expected.
- General Hoyt Vandenberg, then-Chief of Staff of the United States Air Force is depicted as attending the August 23 meeting in 1950. He was not present for that particular meeting, being one of the most vocal critics of MacArthur's plan, which is somewhat accurately portrayed in the movie in later scenes.
- The movie depicts the US Navy reaching Inchon bay area under stealth conditions and only firing on the shore defences on the 15th of September. In reality, the Navy had been shelling and bombing Inchon for about several days prior to the operation.
- Soviet-made 203mm B-4 Howitzers were not actually present at the Inchon beaches as the Soviets never really mass-produced enough units for even themselves. The largest artillery pieces the North Koreans could have possibly fielded at the time were A-19 122 mm guns, ML-20 152mm howitzers and former Wehrmacht 15 cm sFH 18 guns.
- Jang-choon gets picked up for extraction via a proto-Fulton system by being directly hooked to a low flying plane. Surface-to-air recovery systems had been in testing since the 1950s, but the first successful extraction of a living human being was recorded in 1961, a decade after the movie takes place.
- Bavarian Fire Drill: Hak-Soo pulls a brief one during the bar standoff by convincing the North Korean response force that the "traitors and spies" are still inside the building fighting. This distracts the enemy squad long enough for X-Ray Team to mow them all down while their backs are turned.
- BFG: The coast of Inchon is heavily defended by an concealed battery of heavy artillery, which proves to be a major obstacle for MacArthur's landing fleet.
- Big Bad: Commander Lim Gye-Jin, the North Korean commander in charge of the defence forces at Incheon, and a Dirty Commie to boot, given that he is established early in the movie as a protégé of Kim Sung-Il himself.
- Big "NO!": Han Cheon-Seon lets out a grief-stricken one when her uncle is publicly executed.
- Bittersweet Ending: All the members of X-Ray are killed and their loved ones will never see them again. However, Jang Hak-Soo was able to avenge his comrade's deaths by killing Gye-Jin before dying and that he and his team's sacrifice enabled Operation Chromite to be a success.
- Chekhov's Gun: The gold-plated Kim Sung-Il watch that Gye-Jin gives to Choi Suk-Joong to reward him for a good haircut and shaving. When a tortured prisoner reveals that he was provided American weapons by a man with a gold watch, this clues in to the Big Bad about who the traitor is.
- Convenient Misfire: Gye-Jin's Mauser C96 jams right as he is about to execute the mortally wounded Hak-Soo, giving the latter time to draw his pistol while the former tries to clear his jam and load new rounds into his gun.
- Defiant to the End:
- The Determinator: MacArthur recounts his experiences visiting the frontline to General Vandenberg, where he came upon a lone Korean teenager in a trench wearing tattered fatigues with no weapon, apparently having stayed in his position for a good amount of time. When asked why he was there, he replied that no one had ordered him to retreat. Feeling moved by the boy's determination, MacArthur then tells him that he would give him whatever he wanted. The boy swiftly replies, "Give me a gun and give me bullets!"
- Dirty Communists: The DPRK forces and their members are given the full evil commie portrayal package. They hate America/capitalism with a passion, prohibit all religion, Would Hit a Girl and execute all those not in line with their core beliefs, even subordinates who had failed them.
- The Dragon: General Jang-choon, who is second in-charge to Lim Gye-Jin. He gets kidnapped by the Joint X-Ray-KLO operatives for his knowledge of the naval mines and then airlifted to be interrogated by American forces.
- Dartboard of Hate: Lim Gye-Jin is seen at one point on a firing range practising with his sidearm on cartoon caricatures of General MacArthur, Syngman Rhee and several other wolfish depictions of the United States.
- Defector from Commie Land: The main protagonist, Captain Jang Hak-Soo, was formerly an officer of the North Korean Army who defected to South Korea after witnessing his father's execution at the hands of his fellow officers.
- In the beginning, Hak-Soo discusses communist literature note with the real Park Nam-Cheol, specifically the book's ending in which the protagonist dies looking into the blue sky whilst describing a beautiful metaphor. Hak-Soo dies in the finale doing exactly that.
- During a victory dinner with North Korean officers and the Inchon hospital staff, Gye-Jin hypothetically asks Nurse Cheon-Seon if her uncle was caught practising Christianity, what would she do, after making it very clear that Gye-Jin was in favour of shooting traitors on the spot. Her uncle is later executed by Gye-Jin when he is outed as a spy.
- Freak Out: Jang-choon has a major one when he finds himself heavily tied up between two posts, begging the team to release him by trying to tell them about the additional defences at Wolmido Island.Ki-seong: This was successful in Wonsan, but it's no guarantee..."
Jang-choon:: What do you mean? What are you doing?
Ki-seong: Your heart might explode.
Jang-choon: Hey! HEY! WHY MIGHT MY HEART EXPLODE? WHY?!?!
*Later, a low-flying plane performs a surface-to-air recovery via hook to the ropes tied to a screaming Jang-choon, hanging in-between the posts.*
- Glory Seeker: MacArthur is accused as being this, accurate to what historians and most people back then thought. The generals from Washington are concerned that his determination to turn the Inchon landings into his own Normandy would result in catastrophic failure. Interestingly, Commander Gye-Jin proposes this trait as the exact reason why the Americans would attempt such a landing at impossible odds.
- Good Guns, Bad Guns: Downplayed; the members of Team X-Ray use weapons like the PPSh-41 and Tokarev-TT pistols while posing as a North Korean inspection team. After their cover is blown, they begin to use weapons provided by the KLO, including the M1911A1, M1 Carbines and M1 Garands later on.
- Played straight with the KPA and the KLO, with KPA commander Lim Gye-Jin using a Mauser C96 as his personal sidearm, and KLO resistance fighters using M1 Thompsons.
- Invoked when two South Korean sympathisers are outed by the KPA due to possessing "Yankee" firearms.
- Heroic Sacrifice: X-Ray's Dwindling Party is marked by such heroic instances.
- Sang-Duek, peppered with submachine gun rounds in his back stays outside the bar and continues firing his PPSh-41 even as he's face down on the floor.
- Ki-seong detonates the hidden TNT on the landing beach, taking himself and the demolition unit stationed there out before the UN forces can land.
- HeelFace Turn: Cheon-Seon finally switches over to the South Korean's side after witnessing her uncle's execution and the subsequent alienation from her peers afterwards.
- Historical Domain Character: General Douglas MacArthur being famously portrayed by Liam Neeson. Kim Il-sung (portrayed by Lee Won-jong) also makes a cameo during the North Korean High Command's discussion of possible American landing sites.
- Hope Spot: After seemingly clearing the landing beach at Inchon of hostiles, Hak-Soo fires the "All Clear!" signal flare to the US Navy and the music swells in triumph... then Hak-Soo gets shot by a wounded Gye-Jin, who proceeds to finish off Bong-Po and engage in one last gunfight with Hak-Soo.
- Kill and Replace: The members of X-Ray disguise themselves as a North Korean inspection team after secretly disposing the real inspection team.
- La Résistance: The KLO (Korean Liasion Office) resistance fighters stationed in Inchon.
- Living MacGuffin: Jang-choon being one of two people with intricate knowledge of Inchon's defences becomes this to the KLO after the naval mine charts are destroyed.
- Mexican Standoff: Minutes after Lim Gye-Jin discovers Jang Hank-Soo's true identity.
- Mutual Kill: Both Hak-Soo and Gye-Jin manage to empty their sidearms into one after the another in their final face-to-face confrontation.
- Nicknaming the Enemy: The North Koreans refer to the US as "Yankees" and the South Koreans as "Yankee dogs". Truth in Television even up to recent events.
- Operation: [Blank]: The titular Operation Chromite.
- Properly Paranoid: All of Lim Gye-Jin's worst fears about pretty much everything happens: the inspection team with a suspicious fixation on Inchon's naval defence turn out to be South Korean spies, and that MacArthur would land the bulk of the UN forces at his port.
- Public Execution: Twice done by the Dirty Commies, to execute various members of the resistance and those they deem traitors to the communist cause. X-Ray members Dae-Soo and Dal-Joong fall victim to this trope after the two are captured.
- Roaring Rampage of Revenge: If the story told by Gye-Jin about what he had heard from the Soviet faction of Korean communist, then Hak-Soo had apparently avenged his father's death by massacring all those responsible before his defection.
- Say My Name: "Dae-Soooo!" When X-Ray members Dae-Soo and Dal-Joong are captured and set to be publicly executed, Dae-Soo begs Dal-Joong to address him by his real name instead of "young master". While hesitant at first, Dal-Joong gives in and cries Dae-Soo's name right as he's shot in the head.
- "Jang Hank-Soo!", says Gye-Jin as he sees the former aiming a mobile artillery cannon directly at his hidden artillery bunker.
- Tanks, but No Tanks: The mockup of a SU-85 Self-Propelled Gun that Hak-Soo and Dae-soo commandeer during the titular operation has a open top design, which was not a standard feature of the SU-series of Soviet tank destroyers. The cannon diameter also suggests a smaller calibre; either the 76mm ZiS-30 AT gun or a 57mm ZiS-4. Averted with the T34-85 medium tank that Gye-Jin himself pilots to counter Hak-Soo's assault gun.
- Thicker Than Water: Inverted by the North Koreans, who insist that their perfect communist ideology is paramount to filial relations."Ideology is thicker than blood."
- Two Scenes, One Dialogue: Both the North Korean HQ higher ups (including Kim Sung-Il himself) and the UN Command HQ are having equally heated discussions about the coming operations; Gye-Jin trying to convince his Supreme Leader on why General MacArthur would land at Inchon; while MacArthur himself is trying to convince the generals from Washington DC precisely why such a risky landing would work.
- Villainous Breakdown: Gye-Jin increasingly gets more desperate as the KLO and X-Ray teams uncover his plans and by the finale is practically frothing at the mouth with pure unadulterated communism to Hak-Soo during their final encounter.Gye-Jin: What's there to communism, HUH? It's all about wanting a better life together, isn't it? Fucking rat... No matter what you Yankee puppets do, the red flag will march forward!
Gye-Jin: Jang Hak-Soo... I sentence you to death, for tainting the people with your betrayal!
- Very Loosely Based on a True Story: Many details like the names of the members, which groups were actually involved and several events were fabricated for the movie, but the epilogue does name the real life people and organisations while dedicating the movie to their memory.
- Worst Aid: Hak-Soo removes a large piece of wooden shrapnel from a wounded Bong-Po, which in reality would only serve to exacerbate the wound further.