Eh, interesting premise, so-so execution.
Looking at it from a purely erotic standpoint, for a game about voyeurism, it leaves a lot to be desired. There's no real animation other than a naked girl moaning and waving her hand, dildo, etc. around her groin, and that gets really old, really fast. It's not sexually sustaining. An improvement would be to vary the animations and add quality to them. They aren't good as is.
Another thing is the pacing; at times, it feels too slow and repetitive. In the beginning, you really just get money, get packages, and spy.
Another off-putting thing would be the "spying" mechanics. It's a gamble whether you find a room that has a girl in it. It's great that the camera pulses and there is an audio pulse as well when you DO find a room, but with a LOT of rooms, and only 4 girls, it gets rather tedious.
I frankly can't play the game too often to progress to the "good" scenes where you befriend the girls and eventually have sex with them, because the gameplay is rather mundane.
It's a good idea generally, I just wish it had more umph to it.
Overall, I give it a 4.6/10. It could be better.