Halfbrick Studios really made a splash with their iPhone debut, Fruit Ninja, and now they've followed it up with a little game called Monster Dash. It's a running game in the vein of Canabalt, but rather than dodging skyscraper jumps and bombs, you're fighting through pixelated monsters while sprinting along. The main addition to the game is a "shoot" button, so in addition to jumping obstacles and gaps as they come up, you can mow down enemies with various weapons, such as the (default) flameburster, uzis, and even a machine gun jetpack (that comes in handy when jumping).
It's a lot of fun (as you'd probably expect if you've played either Canabalt or Fruit Ninja), and the game comes with Halfbrick's requisite polish, including excellent lush graphics and full OpenFeint compatibility. If there's a downside, it's too bad that Halfbrick decided to just stick with the usual arcade formula. It'd be cool if they tried for something a little less shallow and a little more engrossing. This is just a bunch of levels and a chance to rush for the high score; nothing else carries over from one game to the next.
That's just nitpicking, though. Halfbrick has done another great job on this one and pushed the newborn genre forward with their own twist. It's well worth the 99 cents. And if you do buy it, try tapping on the title screen monsters just for fun.