Metal Slug 3 for iOS is a great porting and touch controls are implemented very well. Price and credits could have been better, but if you're looking for a great "run & gun shooter" for your iOS device, Metal Slug 3 is the right answer.
It's just flat-out an exceptional game, even a dozen years after the fact. The control difficulties will make for some annoying miscues, but it's as good as you can expect for this type of game on a touch screen.
For its attention to detail, nostalgia and unashamedly daft story, Metal Gun delivers. It's a shame that it's let down in the final analysis by a rather frustrating joystick, but we still had fun with it.
METAL SLUG 3 is an admirable attempt at bringing SNK's (at the time) swan-song title for the series back to life; the controls don't quite live up to the original Arcade sticks, but it's a small price to pay if you love the series.