Play Plants vs. Zombies (USA) Online

Plants vs. Zombies belongs to the "tower defense" sub-genre of casual games, where the objective is to deploy a series of stationary weapons to protect a structure against hordes of enemies. Plants provide the artillery and can be bought with sun power, the game's currency. The enemies are zombies invading a suburban lawn. At the start of each level, the player starts to plant the available seeds on the lawn in a strategic manner. Zombies slowly begin to appear from the street at the right side, just a few initially, and must be destroyed before they can reach the house on the other side. Sun power icons fall from the sky randomly and must be collected with the mouse to increase the funds. The sunflower can be planted to generate extra units of sun power but doesn't have any attack power against the invading undead. Besides their cost, the seed packs take some time to recharge after being used.

There are several types of offensive plants available. Peashooters are the basic variety, spitting a projectile forwards every few seconds. Variations appear later in the game, shooting several peas at the same time and freezing the enemies, making them move slower. The carnivorous plant gobbles up a zombie when he gets near its gaping mouth, but takes some time to do so, becoming ineffective while busy digesting the corpse. The cherry bomb explodes after being deployed, carbonizing any of the undead surrounding its landing spot. The potato mine is half-buried with a sensor sticking from the top and detonates when one of the walking dead steps on it. Plants can be removed with the shovel to make space for new ones.

Mini-games appear from time to time. There are twenty of them, and most are parodies of well-known casual titles: ZomBotany (1 and 2), Wall-nut Bowling (1 and 2), Slot Machine, It's Raining Seeds, Beghouled, Invisi-ghoul, Seeing Stars, Zombiquarium, Beghouled Twist, Big Trouble Little Zombie, Portal Combat, Column Like You See 'Em, Bobsled Bonanza, Zombie Nimble Zombie Quick, Whack a Zombie, Last Stand, Pogo Party, and Dr. Zomboss's Revenge. After being played once, they become available directly from the main menu.

The game has three gameplay modes. In the main adventure mode, levels get progressively more difficult, and at the end of each one, the player receives a new plant for the arsenal. Puzzle mode has two variations: "Vasebreaker", where the goal is to break the vases scattered on the lawn, to uncover plants or zombies and use the former to fight the latter, and "I, Zombie", where the player controls the zombies against the plants. In survival mode, the zombies attack in turns. After each turn, the player can choose plants from the arsenal. There are three types of survival: normal (one wave per turn, 5 turns) on each of the five maps, hard (two waves per turn, 5 turns) on each of the five maps, and endless (two waves per turn, endless amount of turns) on the pool map.

The Zen Garden stores all the available plants, where they have to be tended, watered, fertilized, sprayed for bugs, and listen to music. When they are happy, they drop coins that can be used to buy more plants and other garden additions.