The only part of the episode that made sense
The only way to understand the sudden change of character in Takumi in episode 11 and 12 (and to salvage what was otherwise a psychological thriller) is to interpret the events in episode 11 and 12 as nothing more than what took place only inside Takumi’s head—instinctive mental self-defense if you will.
… I’d run straight home like a 13 year-old who just got his first copy of Playboy, and real-boot
Although I may consider real-booting her equipped with a mute button. 
Many more of her goodness here.
There's a bit of Takumi is all of us, especially those of us watching this show.
Awhile back I saw the movie A Beautiful Mind where the protagonist suffered from paranoid schizophrenia, part of which materialized into a little girl. What I liked about the movie was that the director had mostly kept the audience confined within the protagonist’s perspective, not willing to spoon feed the audience what was real and what was not, as the protagonist tried painfully to figure it all out. The audience continued to ride with the protagonist in his turmoil throughout the years in the movie until one day he finally unlock his own enigma: that the little girl had never aged a bit; and therefore, everything else that was directly related to her must also had been hallucinated.
There is no truth; only perception of truth.
At this point of the show, it’s nearly impossible to unequivocally determine what is the reality behind Chaos;Head. Most of the scenes so far are from the perspective of the hallucinogenic protagonist Takumi with only a few exception scenes that are not quite consistent themselves anyway. If we can trust the perspectives of Yua at all, then we can make a guess that Takumi is simply suffering from a delusional, existential need to find meaning and importance of his life by projecting that which he has so far been receiving only from the 2D worlds into his 3D world. On the other hand, the perspective of the silver hair girl (is she also FES?), if her perspective is trustworthy at all, suggests that there may just be a real supernatural element at work after all.
At least he has a couch.
Here’s an interesting formula: take a character whose head is so overflowing with scenes from eroge games that he imagines himself waking up to an 2D female character mounting him and hallucinates erotic images of his own sister drinking from his bottle of soda, and put him right into the middle of a gory mystery involving a male corpse stuffed with a fetus and another pierced by iron crosses, then ask what kind of new images can be concocted in his head from a mixture of two of the rawest forms of human instincts: sex and violence. That’s Chaos;Head.
