All the fags claiming this is a horror game. Believe it or not some people is that stupid and think YN is horror just because of that crap, reason as to why I think that question is more important.
I played Yume Nikki before any of that games became popular on the west/before knowing about them, and it never stroke me as horror or horror-ish or anything at all. It has very calm and isolated areas (sky garden, the cliff, flute room), one cheerful place here and there (pink sea for example), and some very odd and surreal events (mars, famicom world, takofuusen). In the whole game, only Face and Uboa stroke me as an element deliberately placed to cause fear, and even then it's still more in common with the whole "dream" theme than horror for the sake of horror. There are no eldritch monsters chasing you (the toriningen can be passive or aggressive, so it's more like it depends on whether or not they're mad at you), there are no supernatural forces trying to destroy you, scare you, hurt you. At most, it fits as a psychological game, but even then I'd have problems calling it "psychological horror" because it's not the main thing in the game.
You explore the psyche of a young girl who doesn't leave her room, that's all. The rest is pure speculation.
Now look at .flow for example. It did strike me more as a horror version of YN simply because there were actually some sort of scary monsters (literally, 怪物 "kaibutsu") chasing you, the whole silent hill ambiance, the blood, the edgy drawings and pikes everywhere, and the corruption appearing in Sabitsuki's real room (some sort of external force affecting her life). And let's not forget the endings, it wasn't just a ".flow" (whatever that is) thing like in Mado's case where everything happened inside her head. A real maid appears in the real world and cuts Sabi's legs. One could argue it's not the real world and she just lost it or whatever but it is presented in that way
Even though the mechanics are literally the same, .flow is actually horror-ish while YN isn't.>>7010
Google ryona and join the fun wagon.