The twist? The protagonist lives next door to the Aibas —a family of four (father, mother, son, daughter) who are all openly, unapologetically perverted. They are not malicious; they are simply "ero" as a lifestyle. The father is a mangaka who draws adult comics, the mother runs a love hotel, the son photographs gravure idols, and the daughter is a budding cosplayer. They see the angel as the ultimate "cosplay prop."
A nameless, 28-year-old hikikomori (shut-in) who has not left his cramped apartment in seven years. He survives on delivery ramen, online freelancing, and a deep library of anime figurines. He is the "NEET" (Not in Education, Employment, or Training) of the title.
The "PC Top" part of the keyword is retrospective. Around 2008-2012, several Japanese DLsite aggregators and English fan-translation hubs ranked games by monthly downloads. This title regularly appeared in the —not because of high-budget animation, but due to word-of-mouth regarding its absurd premise and unique character chemistry.