Read the true route.
Also just to warn you, that 'I'm back after xx years' setting is pretty common in visual novels.
I do agree that the plot was nothing outstanding (there was some magic though) but the characters were definitely the strongest point of Hoshimemo.
Dude, seriously, buy yourself some glasses or explain why you hate its art.
Well, yeah, she's really annoying but at least always cheerful. But I agree, Chinami annoyed me (partially) as well.
This is totally understandable if you dislike incest. Desi is nevertheless not amused.