First of all, its winter time in NHK - talk about the perfect time for the winter affect. o/
Now.. adding a Kashiwa-senpai school scene wasen't something i'd think they'd go and use at this point, but it goes to show they're still going to go the NHK way even though its closer to the way. You could watch this episode and think "wow, Satou's not a Hikikomori anymore", because well.. thats what i thought. They're telling this perfectly, like someone already posted - this whole episode is pretty much just Chapter 16 in a nutshell, with added material to show that the show is drawing the end. Its Understandable that they wouldn't add Satou phoning up Kashiwa-senpai.. but i'll get onto that subject in a few minutes. Overall this was a classic NHK episode for me, the feeling was there from start to finish.
Also, i'd just like to add that the cloths Satou is wearing when he goes outside in this episode are the same as the manga juring the winter. Nice lil' touch there~