This looks wonderful when it works. The lawn dart really looks like it's stabbing into your foot and
coming out. The problem is that the gimmick used to make the dart stick to your foot is smaller than
a nickel. So imagine yourself having to hit a target you can't see from waist high that's smaller
than a nickel. No amount of practice will make you feel confident enough.
The solution
would have been to make the gimmick for your shoe much bigger, like half the size of a playing card.
With a much larger area to work with, you'd have a good safety zone with it. As it stands, you
literally will have to hit a bullseye every time or the trick won't work. The concept is beautiful,
but the execution is lacking.