With each VN picture as a keyframe basis and the script closely following the route, it's clearly a great start for an adaptation.
Then, there's eye candy where it matters.
Too bad I know most of the details of the story, so it somehow decreases the fun provided by surprises, but it remains an excellent watch.
Regarding Assasin, I remember liking him more in the VN. But it might also be because I know what's to come.