The Last Legend: Glitch Apocalypse

Dale Bennett's best friend, Jill Franklin, is a psychic. At least, that's the only way Dale can explain her apparent premonitions. Whenever they enter a new town, Jill not only knows where the best weapons and items are sold, but how much they cost and what kind of weapon they need for the inevitable boss battle that always follows. If they are trying to solve a new puzzle no one in their party has run into before, Jill instantly knows how to complete it, and in good time, too.
Yet Jill's apparent psychic powers are put to the test when Dale's hometown vanishes into thin air without warning, forcing her to reveal the truth: She, Dale, and their friends are characters in a video game, a game Jill has played through so many times that she has memorized everything, from the locations of secret items to helpful glitches that make beating the game so much easier. But now a new glitch has infected the game and Jill doesn't know what caused it, forcing her, Dale, and the other members of their party to go on a quest to find out what caused this glitch and how to stop it.
Yet as the glitch consumes more and more of their world, it may be too late for Dale and his friends to save everyone and everything they know and love from its destructive reach.