Animate Dead: The Devil Gundam can use its nanomachines to reanimate corpses, turning them into zombies to pilot the Death Army mobile suits.
Anticlimax: After the final scenario, Ryusei speaks for all when he hopes that this really is the end, and that you're not going to hear the beep of another message calling you to battle. You do hear a beeping, but it's just Watta's watch reminding him it's teatime. Ryusei gives him a mostly good-natured hit on the head, which Watta's butler responds to in kind.
Armor Is Useless: Shin places a heavier emphasis on dodging capability, thus armor-related parts are useless because they reduce maneuverability.
Awesome, yet Impractical: During an Earth route scenario, Hayato Jin then informs the SRX team that the time has come to change out their engines, saying that only when combined as one can the SRX show its true power. The new engine uses Tronium, which requires a vast gaping plot hole to explain how it could be developed so quickly. The bad news is that at around three minutes of time at full throttle, the engine is likely to meltdown and explode - and the pilots surely won't make it through alive. For wanky game mechanical reasons, this means that the SRX can only stay combined for three turns, and once the pilots separate again they won't be able to recombine that battle.
Came Back Wrong: After the final scenario, Kouji Kabuto is disgusted that the Devil Gundam would revive the dead as zombies, and the psychological effect of doing so is plainly visible on Eiji as he remembers Gale.
Demoted to Extra: Shin Getter Robo, Dancougar, and Trider G7 have no plot relevance in Shin, while Gundam Wing and G Gundam get the bare minimum of its characters. In fact, Heero Yuy is a Secret Character in this game.
Final Boss: Laodecia (Space Route) or the Devil Gundam (Earth Route)
Godzilla Threshold: Ryouma Nagare, for his part, is rather reluctant to invoke the potentially catastrophic might of the Shin Getter, but will admit the aliens pose an even greater threat.
Horrible Judge of Character: Shakti explains that she was in the Angel Halo because she had to be put into the machine in place of her mother the Queen. Londo Bell fills her in on how Char Aznable deceived her into thinking she could stop the fighting and put her mother at ease. Amuro Ray kindly tells her she needs not apologize for cooperating with an apparatus intended to brainwash mankind - it's all Char's fault for leading her into it.
Hot Scientist: Eri Anzai is the world's foremost expert in ancient relics, and is especially famous for advancing the unique notion that the Mu and Atlantean cultures were in fact founded by aliens. When rescued by the protagonists, they see that Anzai is such a stunning beauty, even Daimoji is drooling. It's clear she's better off in their hands than in the clutches of the aliens who pilfered her from Osaka.
Human Aliens: The Balmarians look exactly like humans, which becomes a plot point.
Humans Are Flawed: Master Asia met Domon Kasshu's father Professor Kasshu and Char and figures the latter was where his problems started, coming short on the heels of the signing of the Luna Treaty that guarantees independence and sovereignty for the Earth, Moon, and space colonies. This treaty was enough to bring peace to the war-weary humans, but could not by itself remove the scars of the war. Char, who loved humanity more than anyone, also hated it more, having sacrificed numerous followers and taken many lives himself. Since he possessed vast influence and resources, Master Asia treated him as a representative of humanity. He was led to believe that humans were unstable, destructive beings, and decided to manipulate Kasshu to help nip any potential for trouble in the bud.
Humans Are Warriors: Discussed between Laodecia and Lu Cain in a Space Route scenario. Laodecia says that Lu Cain's father Gresco has been proved right: the humans' fighting ability is beyond reckoning. What's more, the tougher the challenge, the more the humans stand up to it - in short, the aliens are just making the humans stronger.
Leaning on the Fourth Wall: When you take down the first enemy in Scenario 22 of the Earth Route, the enemy will use a Spirit Command. Of course, Zuhl's "galactic" genius is not matched by his assistant, who rapidly starts pushing the wrong buttons. After a while of this (culminating in Tekagen), Zuhl furiously orders his subordinate not to use any more Spirit Commands. All this is done to Ryusei's amusement.
Let's You and Him Fight: Domon encounters Heero in Scenario 8 and asks him a few questions. Heero remains quiet and attempts to exterminate Domon, kickstarting the Gundam fight.
Love Makes You Crazy: If Usso fights Laodecia in the final Space Scenario, Fala will show up, vowing to pay back the debt she owes Laodecia. When Usso protests, she tells the little boy to shut up, saying that only a strong man like Laodecia can satisfy her - and Tashiro wasn't up to the task.
Mistaken for Gay: It turns out that what Lu Cain was after was in the university database, which Ryusei plays off as just minor breaking-and-entering. Once again, Rai lambasts Ryusei's foolishness, and when Sanshiro weakly agrees, the dialogue awkwardly comes out that Ryusei has implied that Rai prefers men. No excuse can save Ryusei from a severe verbal bout.
Mutually Exclusive Party Members: In scenario 28 of the Earth Route, Domon is willing to settle the score with Allenbie, and not just as a game, but Rain isn't buying it and storms off. Domon can either follow Allenbie or Rain. The former is the first step towards recruiting Allenbie, the latter is the first step towards getting Rain in the Rising Gundam.
Not His Sled: Master Asia is an an agent of the Dug government, sent in response to report intelligent life on the planet.
The Only One Allowed to Defeat You: Ghostelo is is this to Eiji Asuka. During one scenario, Ghostelo appears and smacks the supercharged Zakarl out of the way because the Layzner is his prey. Ghostelo has made himself an enemy out of his own allies, and the SRX Team realize they've only got one chance to defeat Lu Cain, something that hasn't succeeded until now, but likely won't succeed yet, causing Daimoji to sortie the rest of the crew, including the Shin Getter Robo.
Pixel Hunt: Shin contains various secrets hidden in certain spots during various scenarios.
Post Script Season: This game takes place after the events of the Dancougar TV series, as in one scenario, Sara commiserates with Usso Evin and his first love being a traitor, but tells Usso that better lovers can be quite close at hand (she, of course, referring to Shinobu).
Rookie Red Ranger: Ryusei Date is the last member to join the original SRX Team and the protagonist of the story. He's pretty much the de facto leader of the group, mostly because his machine is the head of their team's titular robot.
The Quisling: Neo Zeon jumped at the chance to help the Balmarians, as the one and only means to ensure a future for mankind.
Secret Legacy: In the back story of Shin, a certain race fled their homeworld under the threat of Balmar. Split into different factions with different leaders, they attempted to flee. One group fell beneath Balmar's shadow, while another fled to the safety of the Dug. Finally, one staked their lives on traveling to an unknown, distant region of space. This faction formed the Mu culture, and are in fact Domon's ancestors.
Sequel Hook: At the end of the Space Route, Char sends a message to Londo Bell, whom he expects to be in a festive mood, yet unjustified by what Char is convinced has been a horrific mistake for mankind. He reckons they got lucky with this victory, and points out that Balmar is sure to send a second, or third fleet to Earth, without any shortage of firepower. Just how far will Londo Bell's efforts last, he muses, ostentatiously checking himself and claiming sarcastically that sour grapes weren't the intent of the message.
Stay with the Aliens: Since Char is worried about mankind too, in his fashion, he has chosen to accompany the aliens returning to their own worlds. Therefore, he is entrusting Londo Bell with all the alien technology he has been able to amass, telling them to put it to good use for humanity.
Unobtainium: "Tronium" only exists on the planet Tron; unfortunately, Tron vanished due to a meteor impact long ago. This caused the value of Tronium scattered throughout space to skyrocket, especially since it's needed for every warp-capable ship the feuding parts of the Ze Balmary Empire want to send into battle. According to Eiji, a rice-grain sized piece of Tronium is capable of powering over thirty battleships.
Villainous Breakdown: During the final Space Route scenario, Laodecia starts disbelieving this is happening to him, thinking this is a nightmare he'll wake up from as soon as he returns to the Helmoze...except he can't, because the ship fires its main gun and reduces him to particles.