This is a typical TD game with untypical units. You need to protect the garden from the insects. The insects will move along the path and you'll need to build different things to exterminate them before they reach the garden. The things you build are shooting plants and warrior garden gnomes. After being built each of these can be upgraded or sold for the same price getting back all the money you invested in it. The latter lets you change object positions or replace them by other objects whenever you want.