I tested here and it works fine, apart from not doing anything to the Prezi presentation.
Note that you need to keep the focus on the page itself, else Leap won't be running.
Also, you can go to 'Sources' on the chrome dev tools, and open js/leaprezi.js and add a breakpoint to lines 107 and 113. You can also place it in the previous line to check the values of the conditions, as shown below:
Hope it works for you now!