Darwin's Game

Kaname Sudou, an ordinary high school student, receives an invitation email to try a mysterious app called "Darwin's Game." Kaname, upon launching the app, is drawn into a game where players fight one another using superpowers called Sigils. Without knowing the reason for all this, can Kaname survive furious battles against the powerful players who attack him?

(Source: Aniplex of America)
Note: The first episode aired with a runtime of ~48 minutes as opposed to the standard 24 minute long episode.