First of all, I have to say, I love dark and tragic stories (I love Narcissu, Bokurano, Ayu no Monogatari, Misumisou). I started reading Iriya no Sora, UFO no Natsu expecting a dark and tragic story. There is one problem, though. I really can't stomach weak characters. Wish I knew that the protagonist is one of them. Maybe I wouldn't have read it. -.-
Well, the first two volumes where nothing like what I expected. A bland typical rom-com featuring a mysterious girl. What's more, the style of narration feels cheap. The author constantly switches focus away from scenes in their most climatic moments. Imagine a character on the verge of death (this is only an example), tension rises: dun-dun-Dun-DUN-DUN—<flowers-birds-love-and-peace scene that goes for good 30 minutes>—DAAAAH! It's annoying! I can't recall any manga that uses this kind of narration style. Do I have to say that the story is snail slow because of useless scenes? So, if I were to rate only these two volumes I would have given 4/10, not 1/10 because even among all the bad things there are really beautiful scenes like the park scene, or the folk dance scene.
The last two volumes, on the other hand, are much better and much worse at the same time. It's better because narration style gets much more consistent, all events have meaning, pacing is good, there is darkness and tragedy ... BUT, GOD—err, I mean, dear author—WHY HAVEN"T YOU KILLED ASABA?! After the railroad scene, I was reading the novel brimming with hatred, wanting to kill the male lead with my own hands! I had to stop many times just to calm down! The feeling you get while reading this is worse than NTR. In NTR there is porn, I can understand someone enjoying it. However, in this novel there is no porn, there is only heart-wrenching cringe-making sensation.
Having said that, it must look strange that I gave the novel 8/10. But let's be honest, if the story is bad, I wouldn't have felt much about it, right? Bad stories are just boring: you don't feel attached to anyone, you don't feel like killing characters. So, if not for the first two volumes, I would have given the novel 10/10 because volumes 3 and 4 really made me feel something. Still, I hate this novel, wish I haven't read it.
P.S. It reminds me of Evangelion. The same weak male lead, the same Rei, the same Asuka (less important in this story). Unfortunately, unlike Eva, Iriya has the worst ending you can imagine.
P.P.S If you're going to read this, read the visual novel edition (Nintendo DS). It's literally the same thing (word to word), but with music and pictures.