UPDATE: By popular request we have created a demonstration video of the 3D audio effect on our YouTube channel. You can view it by following the link on the YouTube page for our review or directly at - http://www.youtube.com/watch?v=m9IN0A4GZrE

When people ask me, 'Hey, can you recommend something a bit different for my iPhone?' I'll simply tell them to get Papa Sangre, because when it comes to 'unique' it's hard to say that any other App quite matches this one. Almost unlike anything before it, your entire experience relies on your sharp sense of hearing as you blindly navigate through the 'Land of the Dead' in order to save the soul of someone close to you.

Developer 'Somethin' Else' describes the game as the 'ultimate first-person' game and in a way they're perfectly correct as the game is essentially a FPS only without a visible landscape. Your ears take the place of sight as you hone in on your objectives while avoiding traps and monsters designed to end your life. Swiping the top of the screen will turn your character around, allowing you to face a different direction, while tapping alternately on the bottom of the screen will move you forward, either at a cautious pace or a frantic run that can trip you over if you move too fast.

All of this is pulled off thanks to the use of '3D binaural audio', a sound-engineering technique that mimic's your own ability to locate sound around you in a 3D space using only two sources of sound. It's not perfect, but the effect is uncannily effective and given the survival-horror concept it's a great system for ramping up the adrenaline as you hear unseen monsters chasing after you. 

The only drawback is that the game requires the use of headphones as the 'binaural' effect requires stereo output to work correctly. Interestingly, fourth gen iDevices are treated to additional 'effects' thanks to the slightly better processing power, but those with second gen or lower iDevices will be unable to even play the game.

Thanks to the simple controls and sound-based 'visuals' you can play Papa Sangre almost entirely within the realm of your mind and it's hard to truly quantify just how absorbing and terrifying this kind of experience is. Do yourself a favor and take the time to sit somewhere quiet with your headphones and drift down in to the Land of the Dead to experience a true theater of the mind.