That sound effect when the mannequins spot you genuinely made me throw my mouse, meaning this in fact a successful horror game. Well done (Not sure how it fits with the theme tbh, but still)
I'm not really well versed in horror game design, so I can't really give much by way of design feedback. Only thing I will say is after wandering around a bit I didn't really find my way to any sort of end goal. I just kinda wandered aimlessly while avoiding the mannequins. I would recommend using visual cues to guide the player where they need to go.