I had heard good things about this series, and the first installment didn't disappoint. Our protagonist, Sato, is a reclusive college dropout who believes his condition is caused by a conspiracy to turn the masses into nerdy shut-ins using "cute girl" anime and games that lure people away from the normal world. Then he meets Misaki, who offers to help him overcome his reclusive ways, and Yamazaki, his geeky neighbor (who he also knew in high school) who turns him on to the world of dating sim/hentai games with their bevies of charming 2-D girls. Sato vacillates between denying his "hikkikomori" condition and embracing it as he begins to work his way towards something resembling a normal, or at least productive, life with the help of his new acquaintances. Otaku in-jokes and funny-because-it's-true moments abound! I highly recommend it for die-hard anime fans.
"Welcome to the NHK!" is a splendid show that is a great social commentary and provides an insight into several individuals' deranged, lonely lives. The way that each character is so fleshed out and emotionally and mentally unstable in their own little ways makes for an engrossing experience.
What sets NHK apart from any other anime (or movie, for that matter) is the uniqueness in its narrative; it's not an action or a cheesy romance, but a look into a man's life that is riddled with personal problems. Alongside him are the people that he knows and their anxieties and issues that, whether you agree with their point of view, will cause you to look back on your viewing of the show in wonder.
Without a doubt I recommend this show to older viewers who are not bothered by occasional scenes of nudity. A familiarity with the anime and "otaku" world helps, but is not explicitly required to enjoy this gem of a series.