Close Shave Achievement
Win any level after all 5 lawnmowers have been used
As soon as you have 5 parts of the lawn in adventure mode, (i think its the 3rd wave) let the first zombie on each row walk to the end and activate the lawn mower. Once a lawnmower has been destroyed you should then start to build on that row to protect it. Dont worry about your plants being destoryed as the lawmower doesnt affect them.