Plants vs Zombies: How Did PopCap Do it?

It’s almost 9:30 PM as I write this post. The significance of the time is that it is hours after I expected it to be. The reason: I’ve been playing the demo of PopCap’s Plants vs Zombies and didn’t notice the passing of the hours.

If you’re a game developer, the first question on your mind is probably “What did PopCap do so right?” It’s bizarre. Tower Defense games were last year’s Big Thing. They’re old hat now. Everyone made their own Tower Defense game variation to the point that it was becoming its own genre. So how did PopCap take what is essentially a played-out game mechanic, theme it with zombies and plants, and create it’s fastest selling game that is being talked about all over the Internet?

Well, it’s PopCap. I’m sure they prototyped a lot of really bad implementations before hitting on the finished version.

But the game has zombies and cutesy plants. How didn’t this game simply fail at trying to appeal to everyone?

The game was conceived by George Fan, who is also the creator of the IGF award-winning Insaniquarium. So that’s where he went off to! There’s a few interviews with him, although they aren’t terribly in-depth. GameArena and Hobbit Hollow Games managed to discuss the game design and development with Fan, but I would have liked a bit more info. Gamasutra managed to report that the first prototype of the game was completed three years ago in an analysis of Plants vs Zombies.

Three years! No wonder there are so many modes to the game! I bet there were a number of winning prototypes, and the decision was made to include them all. And again, I ask, how did this not fall on its face as trying too hard to be all things to all players?

I have a feeling that the game was being tweaked and changed all the way up until it was finally released. While most players might not notice it, I think the game looks slightly unfinished, as if a few more weeks (!!) of polish would have made it perfect. Sometimes it seems like an animation is missing or a color is off. One complaint I’ve seen online is that the later plants can sometimes be pretty pointless.

On the other hand, what IS in is fantastic. The variety of zombies and plants is amazing. The first time I saw a Dancing Zombie, I was cracking up long enough to distract me from collecting sunshine. It almost cost me the level. The entire game is rich in detail. The plants dance and move, the zombies fall apart as they get destroyed, and the game mechanics even change every so many levels! Suddenly, instead of planting seeds, you’re bowling for zombies or hitting them with mallets as they pop out of graves!

There’s humor, interesting character designs, and a regular reward schedule. The game is pretty active. While most Tower Defense games only let you purchase and place towers, Plants vs Zombies lets you collect sunshine as a resource. Regularly. You’re constantly clicking somewhere on the screen. At the end of most levels, you’re given a new plant, and the next level might introduce a new zombie type. So each level, there is something new to see. And again, the game changes significantly every so many levels. Instead of being able to pick and choose your plants based on resources, you might have a conveyor belt of pre-chosen plants with which to fight off the zombie horde. Instead of planting seeds, you might bowl the Wall-Nut into them.

So even if you are a regular Tower Defense veteran, somehow you won’t get bored by how easy the game is. There’s just too much to do and see! Is the insane variety of everything the secret to the game’s success? Do you want to keep playing just to see what’s next?

Apparently Plants vs Zombies appeals to both casual and non-casual players equally. It’s very easy to get into, and it is very easy to stay in. Like all Tower Defense games, it’s a resource management game. Before a level starts, you can choose which seeds to carry into battle with you. You only have so many slots, so you’ll find yourself choosing between the option of slowing zombies with snow peas or destroying many of the undead with the cherry bomb. When you plant a seed, there is a reload time before you can plant another of the same type (one of those things which intuitively doesn’t make sense outside of the fact that it is a game), so while you might not want to plant a peashooter until you know where the next zombie is coming, guessing correctly means you had enough time to plant a second one before it shows up. Some zombies use props to try to protect themselves or circumvent your defenses. The pole vaulter will jump over the first plant it sees, so the Wall-nut that should be protecting your weaker plants isn’t as effective. The snorkeling zombie can’t be hit by normal shots unless he is out of the water. I know I’ve planted lily pads specifically for this guy to chew on just so my peashooters can take him out as he rises to chow down. Failing that, squashing him with squash was another cheap and effective way to deal with him.

If anything demonstrates my claim that a game can be made more casual by making it more accessible, Plants vs Zombies is it. It does so many things right while providing so much of it to the player in a manageable way. The entire experience is fun and enjoyable.

As an indie, I take heart knowing that a fantastic game like this can be made by a small team, can use what would otherwise be considered an old game mechanic, and set a new standard that appeals to a wide cross-section of players. I hope I can learn more about the day-to-day development of this project. Was it three years of focused development, or was Fan’s team working simultaneously on other games at the same time? Was PopCap getting nervous that this game was taking too long, or were they fully backing the project, giving it as much time as it needed to be good? What can an indie game developer learn from the development of this game? When will we see the Plants vs Zombies post-mortem?