Sorry, I completely wish I hadn't read this. It pissed me off. Rain and the other anonymous are SO right, after all.
No need to apologize, I was pissed off a lot from the ending too, and see why Rain (and other commenters) have this opinion. I felt the whole idea/story of the manga is interesting enough for readers to give it a try--especially if they go in knowing they probably won't like the ending--because this story brought forth a lot of cool ideas and story development that kept me second guessing myself, so regardless of the ending and characters I was glad to have given it a chance.
Enigma is the only word I can think of to describe this. I understand the plot, yet it's still baffling (like much of this world's mysteries) so I am left somewhat unsatisfied with the ending and story progression, but overall the thought process behind this manga--even if some factors hindered the story--was a masterpiece. Some dimensions of the characters were annoying, but flaws make a human; I loved the twist, and the gender ambiguity of the protagonist. I think everyone should at least give it a go, see if you like it.