While the idea isn't go great, you executed it as expected. It looks nice, but the gameplay just isn't so exciting. Rather than just clicking, add unlockable tools like a scythe which cuts the grass as you you slice the mouse across it. And poison which halts the grow speed for a time. Of course to buy these you would use points. Eventually you could even make this 3D where you can spin the camera around you to cut all the grass around you.