Ever17 was the first sci-fi mystery VN of the genre I read. It had some of the most mindblowing twists I've seen in fiction along with some really memorable emotional moments. It's a shame the official release is out of print and really expensive, this VN is one of the best.

The only reason I get this a 9 out of 10 instead of a 10 out of 10 is because I don't like one of the final twists.