Instructions
Fill your entire back row with sunflowers as soon as possible. Sunflowers release sun drops and you need sun to use your arsenal of plants.
Place winter melons on the row next to the sunflowers. Winter melons automatically deploy when a zombie appears. The attacks do large amounts of damage and they also partially freeze foes, slowing them down.
Plant spikerocks on the far right side of the field. Spikerocks damage Gargantuar when he walks on them. Gargantuar must stomp a spikerock four times to destroy it.
Set off a cherry bomb or jalapeno pepper when you see Gargantuar enter the field. These plants normally kill a zombie in one hit, but it takes two strikes to kill Gargantuar.
Kill the imp that Gargantuar throws at your plants. The imp is small and defeated by any basic plant attack. The imp will destroy your plants if you do not kill him quickly.
Collect sun drops to refill your sun power. Wait for your cherry bomb or jalapeno to recharge and then use one of these plants on the Gargantuar to kill him.