Honestly, they all look pretty much alike, making it difficult to tell which Terran is doing what.  In fact, the only distinguishing factors that any of them seem to have is what they wear on their heads.  For example, Mala, the Terran heroine in the movie, walks around with what looks like shards from a broken green vase on her head.  The elders - apparently in honor of their wisdom - have a series of stylish futuristic looking blinking Kangol chapeaus. 

Not that the humans are much easier to differentiate here - the only way you know which one is our hero is that he has a little chunk of his right eyebrow missing - apparently lost to a strange scar that the animators never quite got around to filling in.

Battle for Terra tells the unlikely story of the sudden and heartfelt friendship between an adventurous Terran girl and an Earth fighter pilot.  When they battle each other, Mala saves his life causing the two to suddenly be platonic soulmates - often selling out their own people for their new friend.

Is it realistic?  Not particularly.  Is the animation impressive?  Well, the backgrounds of the strange world and the ships are very impressive, but frankly the characters - both human and alien - look a little cheesy.

Battle for Terra doesn't seem to know what exactly it wants to be.  Too violent and complex for young kids, too ham-handed and stiff for adults, too simplistic and preachy for just about anyone - it occupies an odd little niche in genre fiction.  The movie has some really cool moments, but there should be a lot more of them.  It's worth a view on DVD or cable if you're into this kind of thing.