IMHO, asking users/testers to install a player beforehand is quite a hassle and makes the whole onboarding process clumsy in many cases.
That's the reason why I think we should be able to save prototypes that already contain the player, in the shape of either portable executables (Windows/Mac OS) or app installers (Android/iOS).
So, during the saving process you'd simply have to choose the target platform for your executable/installable Pie.
I think it would solve lots of issues.
What do you think?