Kyuusai no Kyoushitsu

A Japanese teacher named Makoto Noda deals with a chaotic classroom and mockery from students. After a confrontation with a PE teacher results in a head injury, he loses consciousness and awakens in front of an enigmatic window. As he progresses through tasks associated with it, his real-world attributes enhance, and he gains unique items. Noda must use these newfound capabilities to prevent his school from falling apart.