The ideas kept growing, until they realized they needed to be able to put the characters "in any scenario, any situation, for any reason. When you think about it that way, time travel is the obvious answer. It's actually moving both time and place, so when you look at it through that lens it's actually just about funny scenarios."
Part of the conceit of the time travel meant a little less realism at play. While that may seem odd for a game about anthropomorphic plants killing the undead, PopCap actually did consider it. For example, early iterations had the player planting pots on the pirate ship, similar to the roof from the first game, since there's no soil. It even came up with different kinds of upgradeable pots, just like the plants. The team ultimately decided that the pot requirement would be tiring and cut the idea.
The Scarecrow Zombie, from an early seasonal concept
The second big addition was plant food, which grants temporary power-ups in a pinch. Those, and the addition of touch-enabled power-ups like dragging or pinching to attack the zombies, were all part of a conscious effort to make the game a bit more chaotic. The team found that players of the first game would construct their perfect zombie-killing engine and then let it run on its own. For that reason, the stages are more chaotic, but crafted to balance them that way. They're less randomized than the first time around, to ensure against "massive unlucky streaks."
Of course, a much bigger marked difference in PvZ2 comes in its business model. The first game was a standard paid game or app, while PvZ2 has launched as a free-to-play game. Leamer said this was purely based on watching the shifting landscape of casual games, and how they could catch many more players by removing the price barrier. "So it started to seep into the discussion reasonably early on that this might be a way to go, especially for a game with broad appeal like Plants vs Zombies," he said. "Probably about a year before the launch of the game is when decisions started to get made."
Rajagopalan added that the F2P model helped influence the direction. Since they were thinking of ideas that they could continuously expand and iterate on, the multitude of possibilities afforded by the time travel concept seemed like the best fit.
The many iterations of upgradeable pots
"The focus for the team was to create an experience where people would want to monetize, not where people would feel like they had to in order to progress," Leamer said. "We've been really pleased with the results so far. People are having fun, they're playing a lot of the content, and they're choosing to explore some of the premium plants and add those to their arsenal."
Now that the game is released, PopCap has already announced its first expansion into the
A block-pusher, who would mow down plants, split into two zombie concepts: the camel-shield zombies, and the explorer zombie