I'm french, so forgive my mistakes...
I first played this game 6 months ago, and I like it very much.
1-The girl is maybe the most realistic one in dad'n'daughter games I've seen. She's 18, so she knows a few about sex, she's not a virgin, and also, as any girl from petite bourgeoisie, she's a real brat, and she plays with boys desire without knowing where it goes. She's in her experimental stade. She doesn't fall in love with her father without a sense, etc...
2-The drug is a cheat, but not grave. Maybe the plane accident, 'just my daughter and me' on an island would have been enough to make something, but the father would have to be very pushy, and the girl, not made with sugar.
3-I like the violence. The drug is supposed to provoque that, but the father decides to use the drug on her daughter without telling her. So he's a pervert and he's on the way to assume it totally. In fact, the daily routine in a survival mode, face-to-face, creates a strong sexual tension beetween the two, and the dirty night events are jubilants. The last update was particulary dirt. Loved it.
4-I may prefer without Sanity level, because you can be a fuss nearly all the time. But the sanity level has a good point because you had to choose which insanities you wanted to keep in your storyline. There was something esthetic to be obliged to let some scene. For example, you couldn't probe her asshole, and talk about sex with her the day after. Now you can, and in a way, it's absolutely not the same gameplay.
Really good game, Keep on