Icaro is a piece of collaboration between Moebius (real name, Jean Giraud), creating the story, and Jiro Taniguchi, being responsible for the art. The concept of a team effort between both famous french writer and japanese mangaka sure raises the bar of expectation for this manga alot, which is eventually the reason why the reader would be left with bitter taste at it's end, both creators are masters in their respective genres, but this work cerntainly doesn't solidify their fame.
The synopsys sounds grand, complex and intriguing, and nothing like that can be said for the actual content of the story, it
does try to be metaphorical, but it's too scarse to even feel coherent. Also alot of worldbuilding concepts are thrown in the fray, but almost none of them pay off or even has any value for the plot and it's progression. The story is far too simple to be worth mentioning as such.
The art for this manga is in great detail and it's gorgeous, the only selling point of this whole work that deserves it's unconditional praise.
The characters are very basic, bland and uninteresting, some of them have odd quirks which bear no meaning to the story's worth, and half of the supporting cast is introduced, whithout not having any reason to exist in this story.
The potential that was ruined with this story is major, and the great art cannot hold the manga's worth by itself. It starts grand, and bombastic, and it's end is too simple and uninteresting, this manga is not worth it's time, I do only reccomend it to people who are completionists or to those who enjoy Jiro Taniguchi's works in general.