Plants vs. Zombies is a tower defense video game developed by PopCap Games. The player takes the role of a homeowner charged with defending their home, using an arsenal of plants that can attack, impede, or kill the invading zombies. The game consists of multiple levels, each with a set number of zombies that the player must defeat before they reach the house. The player must strategically place different types of plants on the lawn in order to create an effective defense against the advancing zombies. Plants may also help protect other plants, and some plants are specialised in attacking specific types of zombies. The player can also collect in-game currency that can be used to purchase upgrades, additional plants, and power-ups.