Plants vs. Zombies is a tower defense video game developed and originally published by PopCap Games for Microsoft Windows and OS X. The game involves homeowners who use a variety of different plants to prevent an army of zombies from entering their houses and "eating their brains". It was first released on May 5, 2009, and made available on Steam on the same day. A version for iOS was released in February 2010, and an HD version for the iPad. An extended Xbox Live Arcade version introducing new gameplay modes and features was released on September 8, 2010. PopCap released a Nintendo DS version on January 18, 2011 with content unique to the platform. The PlayStation 3 version was released in February 2011 also with added new co-op and versus modes found in the Xbox 360 version. An Android version of the game was released on May 31, 2011 on the Amazon Appstore, while it was also released to the Android Market on December 14, 2011. On February 16, 2012, a version was released for BlackBerry PlayBook. Later, a BlackBerry smartphone version of the game was released on January 2013 following the launch of BlackBerry 10. Furthermore, both the original Windows and Mac version of the game have been re-released with additional content in a Game of the Year version. In January 2015, a free ad-supported version of the game was released for iOS.