Your GUI is so so so sweet. Sure game is good too but GUI is so so sweet :)
Interesting puzzle with smooth meditative gameplay. Good levels design.
Cool stylish graphics.
The only odd part is that the grass is not 'mowed'. It is uprooted, leaving bare brown dirt! Maybe change the 'mowed' tile to be the same light green color that is under the trees instead.
This is bouring to me to other people it might not be bouring but this is my opinion.
Controls are flawed. The mower has a hard time finding the tile I am hovering over. Also has a nasty habit of randomly releasing when I'm dragging it into position