Thanks for the bug report! I've been meaning to fix a few small bugs in DIG_IT and bring over my new packaging scripts so it's easier to push updates. I had considered limiting screen changes to the Y axis, since that would also play into the vertical nature of the screen (and make more sense for my planned iOS port which hasn't happened yet).
Thanks for playing and caring enough to say so. I won't really consider DIG_IT "done" until I get map export working, I think.