Com2Us is a Korean publisher that's produced some quality iPhone titles, and its latest release, Third Blade, keeps that trend going. Unfortunately, there's not a lot of original iPhone gameplay here (it's a traditional beat-em-up, though there are some nice RPG elements as you go), but while the actual game style is pretty well traveled, the action is well-done anyway. With an on-screen analog control and three different blade types that you can use to hack and slash through the well-rendered enemies, there's plenty of fun to be had, especially if you're up for a relatively hardcore action experience.
Each of the three blades that you can use (a faster dual wield, a stronger one-hand sword and a huge, but slow, two-hand "buster sword") also levels up, and as the game goes along, there are also abilities to uncover and use against the enemies you meet. The enemies themselves are kind of repetitive (though I find most action games repetitive in this way -- it's more about the moves you can pull off rather than the variety of bad guys you come across, I think), but the graphics look great, and the hack-and-slash action is satisfying.
There are a few modes to play with, Game Center is integrated, and Com2Us says that more content will be available in the app soon. Third Blade is a more hardcore experience than your standard casual iOS action game, but for those looking for a little bit tougher action experience, it's worth the US$2.99 to download and play.