It pretty much screws the story up a lot. The mangaka didn't do a good job. Kotonoha was never as cold and bitchy as the last 2 chapters show her. And Yuuki never had a crush on her in the original story (he did but the feelings for her vanished), he had always had a crush on Roka. At least they ended up together, that fixes a lot of things. But still, it really could have been better. I'd recommend you to play (or watch a playthrough of) the VN. It's a lot better.
It pretty much screws the story up a lot. The mangaka didn't do a good job. Kotonoha was never as cold and bitchy as the last 2 chapters show her. And Yuuki never had a crush on her in the original story (he did but the feelings for her vanished), he had always had a crush on Roka. At least they ended up together, that fixes a lot of things. But still, it really could have been better. I'd recommend you to play (or watch a playthrough of) the VN. It's a lot better.