It's been a while since I last read this. The way it's set up is so good.
It feels more or less like a normal, slightly tongue-in-cheek take on "love-comedy" manga. (I'd hesitate to call it comedic. Or, y'know, in any way romantic. But that's neither here nor there.) The pseudo-4th-wall-breaking is used in a way that seems like it's just satirizing the genre.
But as it goes on there's a persistent feeling of dread growing that really starts making itself apparent when Megumi begins to literally see protagonist-kun differently. Cue the whole "demoted to an extra" thing and it becomes clear that this is not just satire.
It's a really great concept that leaves me wanting more, but it's not really something you could make much of a series out of. It only really works on its own, or as part of some sort of meta horror anthology. I just wish there was more like it.