Awesome idea, bad execution. Waste of money for now.
If the app isnt open it doesnt work so you can either drain your battery and hear a quiet voice when you yell Marco at the top of your lungs or you can keep the money and buy a better app. App is romanticised in the description..
Jelly caaaaaaaaaaar!!!!!!! about
Marco Polo: Find Your Phone by Shouting MARCO!, v2.0.1