Interesting little game - this could go in some really interesting directions. Nice simple use of sound and graphics -well done. The thing I wished for most was a score/par system, to measure my success against (and then a re-try button if I didn't make a level within par). Also, I think I would have liked it more if there were two phases - first a mowing phase, and then a putting phase, and you had to pre-think all your mowing before the putting. Was there any cost to the mowing? Could you just clean out the entire area? I did use the un-mowed grass a couple times, tactically, when I knew I wanted a breaking mechanic in case I was in danger if I putted too hard.
There might be a small bug where the lawn mower gets a little confused when you mow outside the play area... when I returned the mouse to the area sometimes it seemed the mower wasn't mowing.