Plants vs. Zombies (PC/Mac) is a new tower defense-modeled game available from Pop Cap Games. The premise is very simple: you own a home. Zombies are invading. Your only line of defense is an ever-expanding array of plants that can stop the zombies from reaching your home. Ward off each wave of zombies by collecting sunlight, essential for growing plants, and earn money to expand your arsenal.

What makes Plants vs Zombies an engaging game is the variety of enemies and plants available. New zombies are added with unique traits almost every stage that require a certain combination of plants to eliminate. For example, one zombie started carrying around a screen door, requiring a plant that can spray a mist of poison through the screen. Another rides on a balloon, requiring a plant that acts as a fan to blow him off the playing field.

The game is comprised of levels with slight variations in play: level one is a sunny day with a full yard of plant-able space, while level two shifts to the night and requires an entirely different series of plants. A swimming pool is added in level three, and level five jumps to the rooftop. The size of the field widens or shrinks to add even more difficulty and gameplay variety. An extra row to attack from is one thing, but having fog cover half the field so your playing blind is quite another.

Plants vs. Zombies is not a scary game. It's more in line with the goofy humor of Zombies Ate My Neighbors, with zombies riding dolphins or zombie football players. Before the final stage of each level, you receive a note from the zombies that tends to be pretty funny. The animation is cute and the sound design appropriate. It's rare to find a budget title with a good soundtrack and Plants vs. Zombies is one of them.

The game comes as a download from PopCap Games for $20, with the option to order a back-up disc for an extra $8. As always, PopCap offers an hour long demo version of the game to play. Unfortunately, my favorite glitch of PopCap, wherein you could play the game straight through and not be asked to pay for it until you logged out, no longer applies. The game is well worth the full price.