PopCap CEO Dave Roberts discussed Plants vs. Zombies 2's free-to-play business model with GeekWire last week, mentioning both the game's swift adoption rate and the ire it has inspired from some fans.

"I don't think anyone at EA has seen anything go up that fast to the top downloads," Roberts said. "My guess, by lunch [on launch day], we will have hit the same number of downloads that it took us five months to hit in the first version. It probably took us close to a year to hit that number on the PC."

While noting that many view free-to-play as "evil," Robers pointed out that the majority of the top-grossing games in the App Store are free-to-play. "People have decided that free-to-play is a better way for them to monetize. And, some of the purists would argue that the industry has made them do that."

Roberts suggested there are "ways to abuse any business model, and people sometimes say: 'Yeah, you can do horrible things with that.' Yeah, of course you can ... With PvZ we have a pretty important brand here and we are trying to protect it."

PvZ2 is currently available for iOS devices and will cross-pollinate to other platforms "later this year and beyond."