Thanks for your input, the Stop motion studio app is actually quite powerful, it has different frame rate and resolution settings, titles, effects, drawing tools, a masking option, and even a (very basic) green screen option. Part of the problem was that my custom build iPod stand was too light and kept moving around. Also this film was shot at 6fps which is kind of slow, I usually try to do at least 8 or 10fps but I didn't have time, and at the time I had very little knowledge of walk cycles or easing, and I completely misjudged the amount I needed to move the car between frames.
It served it purpose though, and inspired some younger children to make their very own stop motion.

“But the enterprise in which I’m about to embark on is fraught with imminent peril.”