This is great! You took a known trope (the farming village) and turned it into something very original. With the game mechanics, you force the player to think in curly ways to optimize. It feels like a challenge, and its great fun.
One thing though; I really don't like the farmers walking on walls. The crops growing on walls are fine (its like that in real life too), but walking on walls is too off-worldish (granted its on a floating island, but anyway).
It would be nice to have specific challenges set, and perhaps a scoreboard.
Oh, and the simplicity is wonderful. Right in the beginning I wondered why there were no upgrades, and no more advanced technology to master other than the cattle. But suddenly I dont miss any of those. Instead, the game feels just right.