Its glacier slow on my gen 1 iPhone. So slow as almost be unusable. Dragging cards is painful. Im not sure what tech they are using, but this feels (and looks) like a web app, not a native Cocoa app. (Controls are non standard, etc.) It could have been written in Flash or something and coverted to run on iPhone. Whatever it is, it is poor. It works, but barely. If it was free it might be worth it for occasional play, but I regret paying for it. It was the only 40 Thieves I could find, though, and I love that version of solitaire. I guess Ill keep looking.