The end is horrible. Not in the null sense but in the sense "poor thing".
Haru only spent his time waiting, waiting and still waiting. All this to get nothing at the end. "Kawaisou"
He couldn't have had his ex-girlfriend from when he was in college and won't get Mahoro either. He will lose 20 years of his life for nothing to wait for. The only good thing is that he had an extraordinary experience and met someone extraordinary.
I'm used to the author. Happy endings aren't his thing. But that is not to say that it is not good.