A few thoughts, if you're interested..
I think a "start again" button might be nice - since the most critical choice is the first square, undoing a square at a time can seem a bit lacking by the time you hit level 30 :)
Seems a bit sluggish.
Took me a little while to understand you touch only the earth squares, not the roads and houses, maybe that could be clearer in the tutorial (or maybe it's just me)
The video on the app store - might be better to include some footage of the tutorial, it didn't make much sense to me before I understood how the game worked.
Anyway, I spent an hour or so with it, so I guess it has some sort of appeal.. Good luck!