The light novel, anime, and manga of Gate all contain a number of references to other works of fiction, both Japanese and foreign. Below is a list of confirmed and suspected references to other works in the light novel, anime, and/or manga.
The Japan Self-Defense Forces 4th Combat Teams' helicopter forces play Wagner's Ride of the Valkyries when they attack the bandit forces during the Battle of Italica. This is a reference to a scene in the movie Apocalypse Now, which the helicopter forces of the US military attack Viet Cong troops, in a very similar scene.
The commander of the JSDF forces in the Special Region further references the movie by asking if the commander of the 4th is possessed by the ghost of Lieutenant Colonel Kilgore, a reckless, eccentric air cavalry commander in the same film. A JSDF soldier also quote Apocalypse Now when explaining that he sits on his helmet to avoid "getting his balls blown off".
Full Metal Jacket
A chocolate bar given to Noriko Mochizuki by a JSDF soldier after her rescue is of the "Full Metal Choco" brand, featuring the likeness of Gunnery Sergeant Hartman, the famous drill sergeant played by R. Lee Ermey in the movie Full Metal Jacket.
Pina's quote, "Those who run are traitors, those who stay are scheming traitors" is also reference to the movie in which the original quote, "Anyone who runs is a VC (Viet Cong), anyone who stands still is a well disciplined VC," is used.
James Cameron's Avatar
A scene of Lt. Colonel Shunya Kengun drinking coffee in the fifth episode closely resembles a scene featuring Colonel Miles Quaritch in James Cameron's Avatar.
The scene in the second episode where Yōji Itami and Takeo Kurata sing the Mei-Com opening in the Toyota high mobility vehicle may be reference to a scene in which a pair of US soldier break into song while riding in a Humvee in the movie Generation Kill.
Call of Duty: Modern Warfare 2
Sōichirō Kuwahara describes the Flame Dragon as a "one-headed King Ghidorah", referring to the monster from the Godzilla series of films. He also states that "The JSDF has a tradition of fighting giant monsters", further referencing the films.
Mobile Suit Gundam
Sword Art Online
The anime version of Sherry Tyueli greatly resembles the character Silica from Sword Art Online, and also shares her seiyuu.
During the siege of Italica, Itami and his squad often refer themselves as seven samurai like in the movie since they are defending Italica from the large horde of bandits much like seven ronin that hired by villagers try to defend a village from bandits.
The JSDF special forces call signs are named for the classes of servant in the anime Fate/Stay Night- "Saber, Lancer, Archer, Berserker, Caster, Assassin, and Rider". Itami is given the call sign "Avenger", the name of a eighth class of servant.
During the Hakone Incident, the Japanese Special Forces Group use the code phrase "Attention all servants. The grail has been filled." Presumable another reference to Fate/Zero or Fate/Stay Night that matches their use of the servant's classes. This reference continues on later such as how, during the Bombing of the Imperial Senate, one of the JSDF F-4 Phantom jet fighters' call sign was Saber.
Lelei La Lelena uses her magic to levitate the weapons of those who had failed to kill the Flame Dragon in the past and propel them towards the target like a storm of flying blades, similar to Archer's "Unlimited Blade Works" attack.
JoJo's Bizarre Adventures
After Rory goes on a rampage against foreign special forces during the Hakone incident, the Japanese Minister of Defense asks if she "put on the stone mask and feeds on blood", referencing the anime JoJo's Bizarre Adventures
Lord of the Rings
In the manga, a JSDF soldier is seen watching a DVD during before the Battle of Alnus Hill, in which the dialogue refers to a character named "Frodo". This may be a references to the character of the same name in J.R.R. Tolkien's Lord of the Rings series of fantasy novels, and the associated movie series.
A Song of Ice and Fire/Game of Thrones
The poisoning by of Emperor Molt Sol Augustus by drinking poisoned wine is similar to that of death King Joffrey Baratheon in George R.R. Martin's fantasy novel series A Song of Ice and Fire and the associated TV series Game of Thrones. Ironically, it is not the Emperor himself, but his son, Zorzal El Caesar, who is himself reminiscent of Joffrey Baratheon- both characters a arrogant, blonde-haired young men with a sadistic personality, who relish in bringing violence on others, but cave when faced with violence themselves.
The anime version of Molt Sol Augustus greatly resembles Tywin Lannister as portrayed in the Game of Thrones TV series, albeit a "younger version".
The first name of Hodor Marceau may be also be a reference to a character of the same name in A Song of Ice and Fire, though the two characters are nothing alike.
Yoji Itami loses a mobile RPG game because he is out of credits purchased with actual money, and unable to even move. This is poking fun at the increasing number of mobile games requiring the player to spend actual money just to make the game playable- i.e. on lives, items etc.
When Rory sits on Yoji's lap during the Third Episode of Gate, an exacerbated Yoji tells her not to touch his pistol, then, shortly afterwards, not to touch him "there". This could be a reference to the common one-liner and sexual pun "Is that a gun in you're pocket or are you just happy to see me", originally a stereotypical one liner of prostitutes in westerns, its has since gained wider use, usually in a humorous manner. In this case, it is somewhat ironic, as it actually is a gun, and Yoji is not at all happy with Rory's antics at the time.
Ace Combat 6: Fires of Liberation
Julius Caesar's De Bello Gallico
The panel from the Manga were Tyuule is naked kneeling before Zorzal, offering her sword to him as a form of subjugation is based on a description from Julius Ceasar's De Bello Galico (the Gallic War). In this commentary, Julius Caesar descries how gallic Warchiefs surrender by kneeling naked before him and his officers to show submission by offer their families holy swords. This description is the basis for some Artworks, which influced the scene from the Manga.