The premise of this story is actually more interesting than most. Usually, you just see some loser get an app that hypnotizes people without any drawbacks or costs. Here, the janitor has limitations on his abilities, and he grows them by putting people in despair and "offering up their hearts". This is actually interesting enough that I'd want to see a proper story told about using magical powers to put people in despair.
Holy Shit. The detail on everything in this was so astonishingly good. When I read the title I didn't expect much but I had a little faith since this was coming from the same person that did near show-accurate doujin of Konosuba and man was I blow away. Like I said before the detail on everything is where it shines. Small things like the designs of the candies and how the app ACTUAL looks like when activated on the phone: /s/c5e3a03af3/1874132-11 , the metaphorical visualization of the MC attempting to control Hime /s/e42a75e9fe/1874132-36 or even Hime's soul crushing realization of what just happened to her: /s/2df163d8b2/1874132-50
Decilitre was already one of my favs but with seeing this level of detail he can just add to hentai I'm really looking forward to all his original manga.