"Just when you thought it was safe ZA! is back! Lovers of zombies and tower defense-style games combined have a second chance to tear into more zombies with more weapons and in more locations than ever before.
7 turrets (3 new, including the Pulsewave)
New upgrades to super turrets
4 maps of varying sizes including Backyard and Trailer Park
Hordes of challenges, 5 for each map
6 zombie types (4 new, including the Hound and Cheerleader)
Instantaneous save when quitting the app
Online high scores list for each map, local lists for challenges and personal records
Automatic iPod music support (Just play your music and start the game)
3.0 USERS!! Additional iPod music playback option
IUGO high-quality and polish"
Source: The Developer Website.