Defend your lawn against drunk people that either want to throw bottles or want to release their pressure in your garden.
Don't let them pollute your lawn, If it takes too much damage you lose.
The game is sorted in two phases in the first you defend your lawn and in the second you can prepare your defenses. You can choose violence and replace your plants with turrets or go the kind way and build some trashcans and portable toilets to distract them from your garden.