Sword Art Online
In the near future, a Virtual Reality Massive Multiplayer Online Role-Playing Game (VRMMORPG) called Sword Art Online has been released where players can control their avatars through brain waves using technology called "NerveGear." When players enter the game, they discover they cannot log out, as the game creator is holding them captive. To escape, players must beat the game by defeating each boss on all 100 floors; however, if they die in the game, they die in real life too. Their struggle for survival starts now...
(Source: Crunchyroll, modified)