These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Complete Monster: Norose is a sneering, arrogant, sadistic bastard with a god complex who specializes in Mind Rape, especially of young girls. What he did to Sena's family (and most especially the amusement he felt about it) was so far over the Moral Event Horizon that it begs belief and that was one of the first things that the audience knew about him!
Idiot Plot: Most of the plot consists of Takumi trying to get away from everyone who could help him due to his paranoia.
Jerkass Woobie: Takumi isn't made out to be the most appealing protagonist; he's an antisocial, cowardly otaku who at first is really only concerned about maintaining his lifestyle. At the same time he's put through a fair amount of trials, accused of murder, and pretty much thrust into plot pretty forcefully. Not to mention finding out he's a delusion.
Moral Event Horizon: Norose's treatment of Nana when Rimi comes to rescue her. You can only really go downhill from there.
Paranoia Fuel: The fact that the main character is paranoid, everything is seen from his perspective and he is not real