It appears that you do not have the Flash player plugin installed in your web browser. If you get Flash now, you can come back and play the game when you're finished! :)
This is a highly faithful Flash remake of the 'classic' ZX Spectrum game that got a whopping mark of 9/10 in the April 1988 issue of Your Sinclair. I couldn't resist making my own 'tribute'... Originally written by Duncan MacDonald. Go get that grass!
Update: Advanced Lawnmower Simulator has now been unleashed on Facebook with added statistics - take a look here.