A more complete solution

Okay...

So I guess the arrow keys actually do work even in embed mode...?  Here's the deal: the arrow keys work after clicking the green flag.  But if you click out of the area, the arrow keys don't work anymore.  And they don't work again unless you click the green flag and restart or the red stop sign (which also requires you to restart).

So it would seem that you can't "wake up" the play area by just clicking on it.  You'd have to actually click a button in the area that does something.  Could the fix be as simple as adding an HTML button at the bottom that says "Wake Up"?  We're gonna find out!