Possibly, perhaps, because I am no longer in the correct target audience age group range, is the reason I did not enjoy this manga in particular.
The story, of what I read (which is not all), was filled with many plot twists after another, but they seemed to be relevant enough for other people. Unfortunately, for me, it seemed too unreal and strange, too focused on making the main character experience enough tragedy and hardships. But what irked me the most was that the main character was altogether too forgiving, as if he had no other emotions. In the end, despite being curious about his past and the mystery behind the circumstances which made me continue to read in spite of these problems (for me), I decided to quit once this much was revealed because of how improbable it seemed to me of his forgiving nature.
Besides this, one other thing almost made me stop reading entirely, which was the reason for one of the plot twists, which was the answer itself: aliens.
One more complaint would be that the summary is not quite what you might be expecting. That, and the tag "Romance" is not the focus of this series. Rather, it seemed to be the underlying reason for the cause of the problems in the story, but it was not a love story, which I thought was strange considering I believed this was a shoujo when in truth, it was a shounen. It was the art that fooled me, but otherwise, be prepared for that if you are expecting to read this for romance, search elsewhere, as this is not filled with the fluff you might be looking for.
If perhaps I was younger and somewhere closer within the age range of the intended audience, I might have enjoyed it much more, but as I am out of range, it was rather less pleasing.
Although I didn't mean to rant and rave about not enjoying it, again, I'd like to blame it on my age, given other people seemed to enjoy it quite well.