Shibou Yuugi de Meshi wo Kuu.

At just seventeen, Yuki is a professional death game player. She’s survived enough rounds to know that survival is calculation, not luck—and that failure is final. For most players, the games are a nightmare with no escape. For Yuki, they’re simply business. Yet in a world where rooms turn into graves and every choice could be her last, even experience offers no protection.
(Source: Crunchyroll)
Note: The first episode aired with a runtime of ~47 minutes as opposed to the standard 24 minute long episode.