Derek saw Susan in her wedding dress before the ceremony. It may seem like stereotypical bad luck resulting from the dress. But according to the superstition, the groom isn't allowed to see the bride, or he'll get cold feet. The brilliance comes when you take note that Derek indeed got (inexcusably) cold feet later in the movie: the moment Susan became more famous than him, he's already made up his mind he can't marry a girl who casts a big shadow over his own fame. Guess it wasn't just superstition when Susan said it was bad luck to see her in her wedding dress.
There's a lot of people who wonder why Gallaxhar bothered to put Susan in a different outfit before draining the Quantonium from her. Keep in mind that the outfit shrinks with her, which the one she was in before wouldn't have done. And seeing as he already expressed disgust with her form and the clothes she was wearing before wouldn't fit her anymore, he probably wanted to spare himself from the sight. As to answer the how, he probably had something else change her outfit.
The ship's computer, by way of a dozen robot arms of course. It even sounds female.
The spaceship is about to self-destruct. B.O.B comments cheerfully, "I'll see you guys tomorrow", and the joke is that he's an idiot. And he IS, but he's an indestructible idiot. After all that we've seen him go through so far, it's hardly a huge stretch that he'd survive the ship exploding. He's just forgotten they won't.
We've seen him crushed under a giant robot's foot. We've never seen him survive extreme heat or high speed pressure waves. An explosion may still kill him. You could make the same argument that Dr. Cockroach would survive, because the entire point of becoming a cockroach was to have the survivability of cockroaches (which are commonly believed to be able to survive a nuclear war. They can't, but this movie's logic would say that they can, and thus Dr. Cockroach would also).
He's survived explosions, if the prequel short is any indication. He'll just pull himself back together.
In an early scene, General Monger tells Susan not to cry because "it makes [his] knees hurt". It might seem like a nonsequiter, but a lot of injuries or just plain old age can make someone's joints hurt when bad weather is about to roll in—the General was telling Susan not to cry because, at her size, it would be like causing a rainstorm.
The theme song of the series is a case of Fridge Brilliance due to the fact that unlike the film the idea is that the nature of the title is now more about the rivalry between Team Monster and Team Alien.
There are some subtle hints in the film and sequel TV series that Dr. Cockroach has a crush on Susan. He was a human before becoming Cockroach, so his implied feelings for Susan would be understandable.
Some find it strange that Area 52 is massive despite holding less than ten inmates. Even with Insectosaurus it seems excessive - except we've seen the whole place is Crazy-Prepared. The facility is ready for the unlikely event of holding hundreds of monsters, as seen by the multiple cell doors in the main area. And unlike most fictional super prisons, it really is inescapable. It is excessive, that's why it works.
Insectosaurus may have been the first monster captured, suggesting the facility was built to accomodate it, hence why it's spacious enough for Ginormica to comfortably walk around.
Why does B.O.B. mistake Susan for a boy because of her "boobies" (besides him being a non-human blob who's also an idiot)? Since he gestures to the very male Link's chest when he says "look at his boobies", there's a very good chance he thought Susan had man-boobs like Link.
According to Dr. Cockroach and Link, the Invisible Man's body had been in that same chair in the room ever since he died, rotting away. Good thing he's invisible.
But can't they smell him?
Dr. Cockroach is a cockroach, and therefore probably doesn't mind smells — he eats garbage, after all. Link is aquatic, and fish stink too, so he might not mind either. BOB is an idiot, and may not even have olfactory senses.
If aliens hadn't invaded when they did, what are the odds that Susan would have spent her entire life in captivity until she died like the poor Invisible Man did?
