These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
YMMV: This Island Earth
The film contains:
Big Lipped Alligator Moment: While the context makes it clear that the whole "plane turns green and lands itself" was the Metalunans saving Cal because they needed him, the whole incident has pretty much no impact on the plot and is never mentioned after the scene ends. (Lampshaded in MST3K: "I don't want to talk about it any more"). If you'd cut from Cal flying his plane to Cal arriving at his lab, you'd never notice that something was missing.
In the uncut version, while building the interocitor, Cal gets a phone call from a mechanic explaining they couldn't find anything wrong with his plane.
Designated Hero: Cal. The man does nothing, even when his love interest is attacked by a MutAnt.
To be fair, his hands were still magnetized to the metal handlebars during that time.
They Wasted a Perfectly Good Plot: An hour of setup, complete with competing viewpoints from Exeter and Brak, and once they get to Metaluna... it all becomes a "Point and shriek at the aliens" fiesta.