By contrast with the iPod version of Peggle, an overachiever that pushed the very edges of the Click Wheel devices’ limitations, the iPhone version of Peggle is a more ambitious but less than perfectly tuned edition. The graphics have received a major upgrade from the iPod port, not just using every pixel on the iPhone and iPod touch’s 480x320 screens, but actually going further by adding an optional “Zoom” mode: double-tap…