Simply put, this manga is awful. Save yourself some time by reading why. Story In short, it's your typical death game. Students of Akane's classroom are forced into pairs and are to kill each other until one pair survives. The author must have been drunk writing the story, because it's an extremely fast paced mess of a plot with an insane blend of your typical survival/death game tropes that has no meaning or value behind them at all, because all the author did was throw them into their story without any context or buildup behind it. The perpetuator is a girl named Karen whose goal is to...force the transfer student Kusada to be with her after they both survived the previous game? It's irredemably stupid. Karen and Kusada both takes part in the game in which they could have been killed, and Karen ends up using the protagonist Akane to blackmail Kusada into being with her.

Oh, and Akane is magically, romantically attracted to Kusada because the plot needs it to happen, even if Kusada made it clear that she dislikes Akane from the start - just to have Karen expose that they are actually sisters, and Kusada ACTUALLY was looking for her long lost Akane all along! Just... what?

The story ends with Kusada giving into Karen's blackmail, escaping via an exit that's magically a thing for no reason while Akane and another character that's not important at all left as the last pair standing. A timeskip into a future shows us that Akane and Kusada reunites once again, then the story ends.

Who are the game's adminstrators? Why didn't they find out about the exit? If it's established that if the cuffs that locks the pair together is opened, they both die, why didn't it happen to Akane? If the winners get to choose anything they want, why didn't Karen ask for Kusada, or literally anything else that is remotely normal instead of deciding the participants for the next game? How did Karen get into the school Kusada was about to transfer to a long time before she did in the first place? The time limit is one week, but why does it feel like only half a day has passed? Don't know, and the author probably doesn't have an answer.

Character
There's pretty much none. Aside from Akane, Kusada and Karen, every other character serves exactly one, maybe two purposes, before getting killed off right away. Even then there's barely anything that defines the three named characters above. This manga is less emotionally charged than a 5 year old kid playing war with toy soldiers. The romance between Akane and Kusada is forced, awful, gets a wrench thrown into it by suddenly being sisters, and doesn't even get any form of conclusion.

Art
It served its purpose, and that's all there is to it.

Enjoyment
Zero.

Conclusion
A complete waste of time.