You can not argue with an anime that has such beautiful imagination. It reads like an Arthur C. Clarke story, earth's first encounter with alien, and its impact economically, sociologically etc. Like his novels, its a subtle thriller, never revealing too much too soon and always leaving more questions than answers.
To complain about its animation is as shallow as complaining about 2001:space oddysey's special effects. This is an anime that will stimulate the introvert. Those with a vivid imagination will lose themselves in this fantasy. The imagery is is beautiful to me, the sunny blue-green landscapes, cold deserted cities, long stares into the night sky, and the soothing loneliness (an escape from modern chaos)
If you have ever enjoyed any of the following
the imagination of the matrix,
Rendevouz with Rama novel by Arthur C clarke
The world of the Fallout (PC game) series
You will love this anime as much as I did.
Although I wish they had made this into a series, and prevented the abrupt ending that inevitably occurred... squeezing the future of mankind in a 90min screening!