Survival Horror Game manga

I'm a huge fan of survival horror manga, especially centered around a "game", and I'm looking for suggestions. I've already read or am reading:

Imawa no kuni no Alice
Kamisama no iutoori (one and two)
Law of the Yama
Ousama game (one and two)
Online
Tomodachi Game (This isn't exactly horror, but it has that "game" element. And the situation is kind of scary if you think about it.)
Liar Game (Again, not really horror but that "game" thing gets me.)

If you know ant similar horror "game" manga please let me know. (●'◡'●)ﾉ