In "19 Hz" you are left alone in a mansion full of ghosts where your only protection is the lantern you carry with you and your only guidance is the sound of your heartbeats.
"19 Hz" is all about tension. You don't see clearly where you are going. You can't fight your enemies. You need to survive.
Find your way through this maze-like mansion into the garden area, and finally to freedom, while avoiding contacts with the ghosts, but keep in mind, they can also hear your heartbeat.