After watching the first episode of the Anime, I had my hopes up for a new real piece of work. I read the Manga but again, I just got disappointed. I think that authors of works with this kind of themes, simulating MMORPG games, really should have enough experience of this kind of games or at least ask for opinions of peoples with it and good taste of this games.
Story line's start is good enough, a new interesting idea but it becomes sloppy at middle. Events come out of blue and there is no logical theory over the whole created world. It seems that author finds good ideas at middle of work but is unable to connect them smoothly and logically.
Comparing with other works like "Loghorizen" or "SAO" it's far to catch up with expectations of a good work with other available experiences.
There was good potential points in the story, even if neglected, they show the good potential of Author.