The School Days manga begins the same way as the anime and who reads is led to believe that the end will be equal. But the story unfolds in a different way.
Some scenes are true to the anime, some even appeared on TV.
The base is the same: a love triangle that has everything to be just an innocent story turns into a cruel and controversial end. Anyway, the manga is "lighter" with both the adult scenes, both with violence, leaving it understood.
While I was reading the final chapters, hoped that the end was not as inhumane, since the story, as I said before, it presents an evolution without malice.
School Days is a great manga and represents an alternative to the end of the animated version, getting hold attention without using so compelling scenes, as in other versions.