This is really sexy.
I love the wall view, it allows to see a lot of information at once, also it's really easy and intuitive to use, although when seeing one image with the phone in vertical position, I expected to see the next and previous making left and right movements as they are easy to do than up and down.
The zoom and the face recognition are great ideas. The first one is really fast compared to the current Galleries zoom method, where you have to reload the whole image. The second is a nice detail, hope to see this grow and connect with Contacts.
The element movement and rotation is fast and slick (it even rotates while the images are moving). I really hope you can push some of this to the OS interface, so the rotation animation is better and the scroll on the lists can be done without scrollbars.
I also like how you allow the application start and show the images when you launch it, instead of using a Loading, please wait splash. Please, don't use it. Besides that, the image process needs to be faster, or at least, the thumbnail quality should to be a bit better.
Congratulations develop team, there are a lot of great ideas in this "simple" application. Can't wait to hear more of you.
And release early, release often ;-).