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.
Fridge Logic :The movie makes it seem like what Lowell was doing was noble, but if by this point humanity could survive without Earth's environment, was killing humans to save the domes justifiable? Possibly a case of Protagonist-Centered Morality.
Or perhaps the message is that human life isn't the only life that matters.
Or, that you can start with a good point, but turn into a Knight Templar suffering from a degree of Sanity Slippage (helped by isolation)... and, thus, not be firing on all cylinders logic-wise (now, who, exactly, am I talking about?). It's not that much of a mystery. It's not supposed to be a happy, totally strings-tied story you can feel comfortable with at the end: it's '70s Sci-Fi. It's Fridge Logic that's meant to segue into Horror once you join the dots, or you're doing it wrong.
Padding: Very, very little of this film actually matters to its plot.
They Wasted a Perfectly Good Plot: The implications of a world with no need for an environment, or a rebel refusing to sacrifice the last piece of such, are ignored entirely in favor of watching Our Hero meander around the dome.
The Saturn effects were originally meant for 2001 but weren't ready in time, so they were used in this movie.
In fact, the film was made with a budget of just one million dollars, and it certainly doesn't look that way.
Fridge Logic: While this troper realizes the point of events recalling the fleet are necessary to advance the plot, the details are still problematic.
The rationale presented for destroying the domes is that they present a 'Hazard to navigation'. Considering where they are(Saturn) AND the vastness of space-this makes no sense of any kind.
The domes themselves, even if custom-built for the project, must have been very costly. They could easily have been repurposed rather than destroyed.
Nuclear detonation of the domes would actually make them MORE of a hazard not less, as instead of one intact easy to spot object, now thousands of small radioactive hazards to navigation now exist. And each freighter was carrying 6 domes each. Which makes one wonder, why were the dome fitted with nuclear det-charges in the first place. The project must have been hugely expensive and represented a substantial investment of time, energy and resources. And considering they represent Earths last intact bio-systems, why makes plans to destroy them?