Cursed place

You have come to a movie screening, but it turns out that the place where horror films are shown is cursed; something resides here that craves your fear. Many before you tried to lock away the evil with a key that was lost somewhere around here, in a place where sounds uncharacteristic of humans echo from every dark corner. Who is there? Maybe your vision deceives you, and no one is there in the darkness? I regret to inform you, but there is indeed someone in the dark, and moreover, it awaits your step into the darkness... You have to figure out what's going on here, find the key to escape this place, and lock away the evil forever. Will you succeed?