Plants vs. Zombies is a tower defense action video game developed and originally published by PopCap Games for Microsoft Windows and Mac OS X. The game involves a homeowner using many varieties of plants to repel an army of zombies. 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 has released a Nintendo DS version on January 18, 2011, that features content unique to the platform. The PlayStation 3 version was released in February 2011. 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. The game received a positive response from critics, and was nominated for multiple Interactive Achievement Awards, alongside receiving praise for its musical score.