The bomber-idol is the only interesting character in my opinion. It didn't seem like she took the task overly serious, and given that it is so ridiculous and the terminology they use is stupid (as Inazuma pointed out), this seems to be the correct attitude.

She also reminds me of heavily of Minnie May Hopkins from Gunsmith Cats, which can't be a bad thing.

The rest feel far more derivative.
- Cool beauty sniper...apparently directly out of HSotD
- Cool beauty swordswoman (a more mature version of Busajima)
- Heavy weapons in a fetish outfit (Sure she likely an actual nurse)
- Angry, self-righteous, too-serious female lead that we've all seen everywhere and is no doubt...a tsundere.

I'm not saying that Oriha is all that original either...she's an idol who is secretly an assassin, but at least explosives is something different, and certainly riskier given her daytime profession. She came off as the much needed comedy relief character. Having the BSDM pervert son listening to her music was a nice, subtle way of revealing her other profession before the no-explanation fire escape performance that otherwise makes her look like an annoying wannabe idol.