Clear the Game, Save Earth

A horror game runs a closed beta, and Leonard Miller is one of the testers. He comes close to dying a dozen times inside it and is the only tester who clears every level. The day he gets back to the real world, the game goes live on Earth. Everyone on the planet is enrolled, whether they signed up or not, and Leonard is pulled back into the dungeons against his will. He goes in with the attributes he maxed out during the beta and a full memory of every stage and every trap. While other players are meeting the game for the first time, he clears the high-level stages with little trouble, keeps his family and friends alive, and starts gathering allies. In the course of this he works out that a higher civilization built the game and has been using Earth as its playground. Closing the game for good means collecting the core crystals and getting through the final level, and he sets out to do that.