The story makes no sense (spoilers)
Ok, I haven't seen the original series, haven't been following Japanese Anime for a while either, but man this story is hard to swallow.
1. The whole premise of man depleted resource of the galaxy and had to go back to Earth is absurd. Does the writer know just how big our galaxy is? There're 400 billion stars in our galaxy, enough to give each of the 500 billion humans (actually I never heard of this number in the movie, just going by IMDB's summary) his/her own star!
2. The movie keeps mentioning human is on the decline, about to die. But Gaia Coalition has weapons that use neutron stars and lasers powered by gas giants! Seriously, this looks like a civilization that is about to go extinct?
3. Detonator #99 is dropped to molten lava where a huge alien monster lives in, we're supposed to believe it still works?
4. Why doesn't the Coalition just disable or destroy the detonators? They at least know where #99 went due to Logan, also #100 is left on Earth unprotected.
5. It's strange that the Coalition wants to destroy the Earth, but hey they're the bad guys. But why do they need a retina implant in Earth orbit to aim their super laser? Don't they know where Earth is relative to Jupiter? Newton could have told them where to aim.
6. Their laser missed twice, which is good, but what's preventing them from firing a 3rd time?
7. I thought everyone (including the alien girl) died near the end, how did they come back? (Also I half expected the fleet and citizens to revolt once they found out the real condition of Earth, yeah I know it's a cliché, but at least it makes sense)