The problem with Facetune (and its ilk) is that every time I've tried to 'tune' someone's face in a manipulation application like this, the end result has been unsatisfying. The secret is probably to be restrained - removing a couple of spots and some freckles may work out OK, but Facetune sets outs its stall to go much, much further, changing face contours, eye and hair colour. My gut feel is that reality is preferable to an air-brushed, tuned version of our friends and family, but your mileage may vary!

From the Store description, here's the feature list:

• Widen or refine your smile
• Whiten and brighten your teeth
• Smooth and rejuvenate your skin
• Remove temporary imperfections like pimples and blemishes
• Change your eye color 
• Remove red and white-eye effects
• Color over grey hair 
• Fill bald patches
• Refine jaw lines 
• Heighten cheek bones and brows 
• Reshape your nose
• Apply any shade of blush and eye shadow 
• Add volume to your lashes and shape your brows 
• Add color to your lips
• Focus the photo on you, by defocusing or blurring the background 
• Improve lighting or add special effects 
• Add unique textures and customizable frames
• Add artistic touches to make your photo your own 
• Instantly share your edited photos with your friends & family through social media or e-mail
• Compare your work with the original photo at every step of the way, with only one tap

The interface and ambition are both there, at least. Moreover there's a wealth of tutorial resources for getting the most from the utility, thanks to Facetune's YouTube channel. As a teaser, here's an overall promo (for the Android version, but you'll get the idea):

Interestingly, Facetune's a commercial purchase with no trial - I'd have expected that, at the very least (for this sort of application), a 'watermarked' trial version would have let people play with the concept, risk-free, for themselves. Ah well, it's only a couple of pounds (in the UK).

You can buy Facetune here in the Windows Phone Store.