ZIM discovers his almighty leaders never had any intention of coming to Earth and he loses confidence in himself for the first time in his life, which is the big break his human nemesis, Dib has been waiting for.
This movie contains 11 potentially triggering events.
No one is crushed to death, but Zim is momentarily squished under a mechanical throne. Red liquid also splatters around, but it is only from a drink that he was shown to be holding a split second before. It is played for comedy, and it all happens very quickly.
There are no babies in the movie. However, Zim and Dib briefly discuss a taco place where GIR ate a baby, and a short audio of a crying baby plays afterwards (not from an actual baby in the scene, but a sound effect for emphasis).
As the Florpus portal starts to pull reality apart during the climax, the movie cycles through different art styles and mediums, such as a sketchy art style and live-action pugs dressed as the main characters.
Professor Membrane's depiction in this movie is actually more positive than in the series, as he's shown to be slightly less neglectful and more supportive of his children (specifically Dib)
The tallest are shown burning in the Florpus at the end of the movie. Although it’s not made explicitly clear if they died, it’s very likely that they didn’t.
Zim's plan in this movie would've probably killed him in the process, and he is shown to be okay with this if it means he'd have completed his mission.
[[Spoilers for the end of the movie]]
The Earth is returned to its rightful place in space, Professor Membrane is returned home to his children, and even Zim returns to Earth without any lasting punishment or harm. Overall the film ends about as well as it can for all involved save the Tallest, who enter the Florpus hole of their own stupidity and never emerge.
Blink and you'll miss it, but red liquid splatters when Zim is squished by a mechanical throne. It isn't blood, but the drink he was holding. He is immediately afterwards shown to be alive and well.