GEM KEEPER, the cool graphic tower defense game. It's currently free.
Get your fingers ready, 'cause it's time to protect the gem!". If you are the fans of the tower defense game and also love free ipad games, this one is another good option for you. Gem Keeper is published by NCSoft Corp, the large online game company who owns several online games such as Linage,AION,guildwars and more. This free ipad games also rewarded as Venture Beat's Top 10 iOS Games of 2011 , don't miss your chance to try this game!!
-3 Difficulties level (Easy,Normal,Hard)
-30 Defense levels
-14 Types of towers
-22 Types of enemy
-And more things that might included in the update patch!