There are dozens if not hundreds of tower defense games on the App Store, but for my money, Kingdom Rush is just about the best of them. It's originally a Flash game that's found a lot of success on iOS, and after a few solid content-filled updates, it now features tons of levels, enemies, units to buy and upgrades to earn as you play along through the game.
And there's even more on the way. Kingdom Rush: Frontiers is a new version of the game due out this spring, and it's gotten a teaser trailer of its own, which you
