Thanks for the reply, kooky panda! I can zoom in and out that way to a point. But when the game starts, I can see about twenty tiles diagonally (on a Kindle Fire HD 8.9" using version 1.0.5.5). Zooming in to the "closest" level shows about nine tiles diagonally, and zooming out after that only shows a maximum of about fourteen tiles. My normal Android phone using DS: Spring zooms in and out without this issue (and automatically zooms out after feeding or expanding).
I can play without zooming out that far, obviously! Just wondering about it because I have read a bunch of Kindle posts in this forum and no one else seems to be mentioning it.