Doreiku - Boku to 23-nin no Dorei
A REAAALLY good find. If you're looking for something different, try this one out for size ;) This is basically about a game where you can enslave anyone, just as long as things don't get out of hand heh
Ou-sama Game - Kigen
Read it in one go. I couldn't sleep anyway for two reasons: first, it's just TOO AMAZING, the way of killings are on point, the art style is beautiful, there's enough mystery to keep you reading, the plot twists are unpredictable... second, it ENDED. Btw this is the prequel of the first manga, "Ousama Game". Read that one first bc this is about the origin of the "Ousama".
Ousama Game ( Kanazawa Nobuaki )
Unsatisfying ending but an enjoying read. There's enough gore to keep you reading, and halfway to the end things got reaaally intense. Like people doing immoral things to save their own skins, and a mystery figure giving out insane commands with their lives on the line. Read the prequel "Ousama Game - Kigen" after this one.
Ibitsu
Relatively short but provides enough goosebumps to keep you from sleeping at night. Basically involves an eerie-looking lady wearing lolita apparel in the trash heap and asking the same question to every passerby, unaware of their coming doom.
Seeking for Death
A horror manga about school girls clinging onto the mc (while clinging onto their lives) and making him decide which of them he'll save. Similar vibe with "School Days". Shitty ending but AMAZING art style. Deaths are average. Needless to say, I always go for yanderes.
Franken Fran
Multiple stories, each with a plot twist at the end. MC is a hawt female version of Frankenstein. Very gory, imagine 'mad scientist performing gruesome experiments on her clients' only this time, the protagonist does so for the sake of 'helping others' and not for spreading terror in humanity.
Tokyo Red Hood
A very disturbing, twisted version of "Little Red Riding Hood". I dropped this early on but I plan on finishing it some other time. Not a big fan of the art. The gore is good tho, and the mc's messed up in the head so it ain't all bad. It's about a little girl's quest on finding "Mr. Wolf", whom she fantasizes on devouring her.
Blood Lad