The first one I'm trying to remember where majority of the school dies and they're forced to play these mini games controlled by these dolls. There are a few survivors, and they're told to meet in the gym where they dress up as mice. A rather large cat appears and they're suppose to shoot something in a hoop or something like that. No one wears the costume except the main character, and it allowed him to communicate with the cat.
The second manga I'm looking for is where the main character participates in a death game due to his sister being in the hospital. Every round the participants lose one of their senses for the duration of the day.
I can provide more information on either of these manga's because I read most of them all the way to the end but I can't seem to remember the titles.