I'm not great at rating games, but here's why I enjoyed this prologue very much:
Interesting story line, characters have a certain depth and captivating dynamics between them, dialogues are well-written with a hint of good humor; graphics are well made with enough attention to detail, just enough animation and no obvious stock material, characters are very attractive and natural, not ridiculously over-featured (I, personally, also enjoy the absence of MILF material

).
To me, this is one of the most interesting recent developments and definitely worth keeping an eye on. Bravo!