Playing a keyboard from the iPad's touch screen is always a bit of a risky proposition. Tiny keys with no tactile separation means that all but the extremely dexterous are likely to experience missed and doubled notes.
Korg has done its damndest to ensure a smooth playing experience, though. The three-octave keyboard can give way to a user-sizable version with thin, normal and thick options (describing the keys, that is, not the users. Ahem.) A slider and octave buttons allow for scrolling up and down the key range.
Additionally, there’s a pair of KAOSS Pads, one of which triggers notes or chords in any of 35 selectable scales set to any of a dozen root keys. In other words, you needn't be blessed with tiny digits nor, in fact, a heck of a lot of musical skill to get good results out of the iPolysix.
Users of iPads 1, 2 and 3 can, of course play the instrument from an attached MIDI controller, either USB via the Camera Connection Kit or using a dedicated device like the IK Multimedia iRig Keys or Akai Synthstation 49 (though the iPolysix is not specifically designed for Synthstation compatibility as some other synths are).