Plants vs. Zombies is a tower defense game where you deploy stationary weapons to protect a lawn against hordes of enemies. The goal is to use the available seeds strategically to plant defensive structures that can withstand the zombies' attack.
The gameplay involves using sun power, collected from icons falling from the sky, to buy plants and other items needed to defend the lawn. Each plant type has its unique abilities and strengths, such as peashooters shooting projectiles or carnivorous plants devouring zombies. You must remove dead plants with a shovel to make space for new ones.
The game features mini-games that parody well-known casual titles, offering a fun break from the main gameplay. There are also three gameplay modes: adventure mode, where levels get progressively harder and you receive new plant types; puzzle mode, which includes "Vasebreaker" and "I, Zombie"; and survival mode, where zombies attack in turns and you choose plants to defend yourself.
The Zen Garden allows you to store and tend to all the available plants, earning coins by making them happy. You can use these coins to buy more plants, garden additions, and other items needed to progress through the game.