If you listen to Boing Boing's Apps for Kids podcast, you know that Jane and I love the iOS app, Kingdom Rush, and its follow-up title, Kingdom Rush Frontiers (They are on Android, too!). The object of these tower defense games is to wisely use your treasure to build different kinds of defense towers and to deploy troops to stop oncoming waves of monstrous invaders. The excellent cartoony graphics and elements of humor add enhance this addictive resource-management challenge.
Today, Armor Games announced that Kingdom Rush Frontiers is free to play on its website. From the press release: "The Kingdom Rush Frontiers Flash version features 15 stages set across three unique terrains, with three epic Boss Fights, over 40 enemy types, nine heroes including six that are unlockable through gameplay and plenty of fun Easter Eggs throughout."