Other assorted things I remember: There is a progress bar that seemingly indicates how much the worlds are "switching" in terms of how game-like they are. Some lady in the real world warns him but later starts acting like an NPC anyway. I think she leaves him a message in the game world with her corpse or something.
should be this https://www.novelupdates.com/series/single-player-only/ but its on hiatus now sadly @drollawake