Because the game is region-locked (originally sold only at Japanese doujin conventions like Comiket and via DLsite), obtaining a legitimate copy requires:

The "Angel" is not a biblical seraph but rather a hapless, often clumsy divine trainee sent from heaven. Her mission varies: reform the NEET, grant him a wish, or collect "faith energy." Crucially, she is innocent, otherworldly, and completely ignorant of human perversion. This ignorance is the engine of the comedy and the ero content. The fish-out-of-water scenario creates a power reversal: the powerless NEET suddenly holds knowledge (earthly, lewd knowledge) that the angel lacks.