Hm, where to start?
The story line was totally rushed, full of deus ex machina and general inexplainability. It does not make sense, to quote one of my favourite south park episodes. It is nothingness stuffed with fancy swords, anime clichés of the worst sort, and misplaced otaku-dom. There are series where all this does not matter that much as the characters hugely support the plot or make up for lack thereof. Here, this was not the case.
The characters are one-dimensional, either lacking completely in background or equipped with some ridiculous excuse for one. There is no real development whatsoever.
The main character is a whiny wimp who cries and gets lost in his stupid daydreams for 10 episodes, being a suspect in a murder case for roughly 6 of them(which was still a bit interesting at least), doubting his own sanity, to suddenly be up against a random evil corporation that wants to take over the world. More crying and confusion ensues in the episodes after that, only to have him evolve into a hero in about 2 minutes in episode 11, without any apparent reason.
There are some attempts at a pseudo-scientific explanation. They fail miserably. Some animes have a point, and some don't but it does not matter as the development during more than makes up for it. Here, we have neither. It's just something that starts out interesting to become a greater and greater bore.