This is definitely a great example of a psychological manga with very good twists, mystery, and best of all- horror. 'Doubt' is a short series that is based on the familiar plot of 'survival games', something you might recognize if you've ever read or heard of Battle Royale.
The purpose is to survive, be the last one standing, but all the while, needing to survive even if you've won.
Keeps you at the edge of your seat, an eager read, definitely among the best in psychological survival game horror genres.
Doubt (tonogai Yoshiki)