Just Here for Godzilla: While the film isn't seen as bad per se by most Gundam fans (both UC fans and in general), odds are that if you ask one why they watched it, they'll respond with something related to Mobile Suit Crossbone Gundam, which is a sequel to this film.
Memetic Loser: Iron Mask is often derided as a pathetic villain, in part due to how his motivation for villainy is that he lost his wife and kids (Often mocked with the phrase "SHE TOOK THE KIDS"), and that he loses to a Gundam that "HAD AFTERIMAGES WITH MASS" due to his ending up shooting himself with his own weapons trying to hit said Gundam.
Bennett the Sage considers the scene where the mother is killed by a falling shell casing to be this, saying it's something he'd expect from a Hanna-Barbera cartoon.
Theo Fairchild's death. After the argument between his wife and Iron Mask concludes he immediately falls face-first onto the ground and dies. It's so jarring and has oddly comedic timing.
Signature Scene: Strangely enough, one of the scenes even anime magazines focused on back in the day was not over the battles or the character drama - but some random mother getting beaned in the head by a stray spent shell from a nearby Federation mobile suit, and dying instantly for being in the wrong place at the wrong time as it orphans her child.