A lot of plot holes!!!! Such apocalypse is going on and how can the school authorities run the school by neglecting such issue. Why only one class in the school. Why the public is acting normal as nothing happened including teachers that students are dying? Only the parents whose children die in front of them remorse for a bit. But they don't take any action the slow up the apocalypse (Well they definitely can;t stop). Was the government sleeping when students of only 'particular schools and classes' were getting killed. It's shown that the game is being played since 30 yrs. At that time pieces of papers were used instead of cellphones. How the heck can a piece of paper kill human instantly??? To many questions unanswered!!!!! These are taken into considerations that the anime setting & plot is of real, present world. Not typical shonen or fantasy world!!!!!