It's no HaruToki3, but not bad.
As an otome (marketed at girls/women) mostly-visual-novel game, it's pretty good. The essential functions (text-skipping options, voice volume options etc.) are all here, the heroine is awesome (i.e. no weak damsel-in-distress, though she's very strong-willed, which some may not like), voice acting is good, and the story is intriguing and a little dark, with a heavy Japanese supernatural flavor to give the typical school setting more heft. The art is very anime-esque, with strong lines and simple shading, but it works very well on the PSP and the CGs are quite nice. If you have the first game's PSP port and/or savefile, you can open up a lot of events relating to the prequel's characters.
My one real issue with Mizu no Senritsu 2 is that the battle system introduced a decent way into the game is kind of weak; being mostly luck-based and extremely straightforward (no heals or indeed anything more complicated than rock-paper-scissors plus a super attack), it ranges from frustratingly random to just boring.
Overall, though, it's quite a good otome game, especially if you're into the mythology and folktales of Japan and want a strong heroine.
日版 
