Storywise, it doesn't hold up to the movies it borrows plot points from. As the story is basically every other "white man goes native" archetype, you'll know the entire movie scene-by-scene just by that description, however there are a few things about "Terra" that really bothered me:
1. The aliens are living in perfect harmony but are assaulted by humans for no reason. There's never any reason given why they would need to be abducted and studied, but that's what the humans do to them anyway.
2. The human fighter wildly changes size from scene to scene for the entire movie, to the point where it starts getting distracting.
3. For plot convenience's sake the pilot's personal Johnny 5 knows sperm lady's language and has a laser beam that can teach her human speak in a few seconds and knows how to build a working device for filtering out air from the native atmosphere, using clay and a plot convenience plant that the female lead gathers and assembles without any problem.
4. The human general (wisely I might add) takes control from the incompetent senate(?) which is unable to decide on the only course of action available at this point. This is supposed to be the cementing of the general's character as a power-hungry warmonger, but in the context of this movie he makes a lot of sense.
Also, we never get to know anything about the aliens, other than that they shun technology but are somehow innately adept at constructing advanced mechanical constructs out of clay and wood. They are completely peaceful yet keeps a fleet of advanced warships and highly trained military somehow completely hidden from their public. This standing army makes no sense since they're completely peaceful (as war is an almost foreign concept to the main female character), have no natural enemies and don't have any crime. However, it's explained away in one sentence later on by the elder saying something about learning from the past to not repeat it, or something along those lines. They can apparently fly, without wings or any other way of actually doing so. The planet has gravity, as the other creatures that we're shown need wings to fly and the buildings are designed with creatures in mind who walk on the ground. They can also hear without having any ears, which doesn't make any sense. It doesn't help that they use mouths with similar enough human-like vocal chords and sounds to replicate our language, simply by being zapped by magical language-teaching lasers.
As for the humans, they need the planet in order to survive as a species, as they've run out of time with their colony ship falling apart and their air supply failing fast. We're told they've got weeks to go before they asphyxiate, and that it would take seven days for the terraformer to make the planet's atmosphere breathable for humans. This is where the supposed dilemma for the main character in all of these movies comes is presented for the viewers. However, unlike films like FernGully, where the humans cut down rain forest for profit, or Avatar where they killed natives for unobtanium, here we are just trying to survive. So, our hero betrays THE ENTIRE HUMAN RACE and fires his missiles on the terraformer, murdering his commanding officer and a staff of completely innocent human beings, assuring the destruction of all humans, everywhere. Oh, but that doesn't happen, as now all of a sudden the human race doesn't need the terraformer, and the entire plot of the movie has been changed to try and not make its main character that much of a genocidal race traitor. Now everything is great because of his high treason, and not only do the humans live in harmony with the sperm people, they magically found a way to instantly construct an atmosphere shield. And as a final middle finger to the viewer we pan over a statue of the arch traitor himself.
I don't get that. I don't understand why anyone would root for the non-humans when given the choice between humans or not. This isn't an analogy for real life intolerance, this isn't the white man holding everyone else down, it's just another "hate the humans"-flick. Personally, I don't care if the sperm people were there first, if every single one of them is a Gandhi sperm with a deep connection to nature. I'll stick with the survival of my race, thank you very much.
I would not recommend this movie to any demographic as there are many more, better films out there with the EXACT same story and characters and setting and dialogue, only with better execution.
Review by Tobias Lovgren from the Internet Movie Database.