I really enjoyed this. I was expecting anything but an economic sim / puzzle. :)
Good graphic design, nice soundtrack.
The font was a little blurry, especially at the smaller sizes. Some of the numbers got very hard to read (is that a 5? a 6? an 8?...).
Beyond that, I have one complaint--without a persistent HUD, having to constantly jump through the menus to check how much money and water I had got really tedious, and I often miscalculated as a result. I realize this is a GB Studio issue and there may not be much you can do about it.