The new Touch (right) with its retina display doesn't look exceptionally remarkable in this shot.
The retina display features a resolution of 640x960. Compared to the previous Touch (320x480), that's twice pixels in each direction, or four times the total pixels.
The retina display is almost completely black when turned off. That's noticeably different from the display of the earlier iPod Touch (left), which is dark gray when turned off.