My first visual novel was Tsukihime - It had some pretty ugly artwork (at least compared to a lot of other VN) but the story was amazing and remains one of my all time favorite VN for this reason. I heard the anime sucked, but have never watched it. -- But the writing, and even the fan translation of Tsukihime is what really wins me over. I love the twists and turns and how unexpected a lot of things ended up being. I loved that it wasn't just straight up romance (though I love slice of life stuff too). This had that extra "something" to push you to keep reading. It had that element of danger and excitement that very few VN bring to the table.
For those who don't know, you play as a young man who has spent most of his life hospitalized with a strange illness. Somewhere along the way, you discover you can see the "life line" of all things - be they living or inanimate objects such as a table etc. And by tracing your finger over the "life line" you cause that item to "die" - or more precisely, you wipe out its existence, so that it's as if the object never existed in the first place.
One day, you see a woman walking down the street, and you don't know why, but you feel compelled to follow her. You know nothing about her, but she bothers you. She makes you really angry, for no reason at all. It's not what she's said or what she's done, nor even the way she's dressed or looked, you just inexplicably have a deep burning hatred towards her the moment you notice her. Before you know what you're doing, you've followed her home, and you brutally attack her, raping and murdering her. You've never hurt anyone before - so naturally, you're a little freaked out, but yet, you also find the experience quite enjoyable.
To your surprise, the next day, the same girl, that you just victimized, comes to your home. Turns out, she is a vampire, and can't be killed. Now she wants restitution for your crime, so she forces you basically to be her servant.
As the story progresses, it reveals the mystery of your power to cut life lines, and reveals what it was that compelled you to murder the girl. Then it's up to you to sort through your feelings for this girl who although your body deems you to hate, your mind wants you to protect.
There's also other girls, including a vampire hunter - among others, and they too all have routes and are dateable characters. There is a lot of tragedy, sadness, and mystery in each route.
The ultimate mystery and plot twist comes about 3/4ths of the way into the game - and you learn things aren't what they appear at all :)
Of course - the final route unlocks only after dating all the girls, which helps to explain everything with one final girl.
Have you played this novel? Did you enjoy it? Were you surprised by some of the plot twists, or did you see them coming?