Very cute! I finished the game, but I forgot how long it said I took. I played it in Chrome.
The mid to late game could use some balancing. Pretty quickly, my willingness to keep clicking the upgrade button became the bottleneck to upgrades, and my computer's ability to simulate 200 dudes running around at high speeds became the bottleneck for buildings. Despite that, the tower levels just shot up due to the intense speed of harvesting.
Some minor nitpicks: bridges aren't refunded when destroyed, and roads are destroyed with no refund when a building is placed over them.
I would like to see more of this game.