Hi there,
Since I have tried to link an object with physics in blender file, each time I press “P” it crash without displaying any message.
The issue appear both on Experimental Evee and latest official version.
Is there any way to print a log file ?
I really want to instance objects that is why I was using links (and following the documentation)
BTW I’m pretty new to this game engine and really like it, so thank you programmers 
mixing 2.8 and 2.79 is a big issue, you could have corrupt blend files.
These days I had this similar problem. By pressing the letter P the game closed without explanation. so I took the whole scene apart and saw that the problem was in the textures.
What happens is that I didn’t want the textures to visualize in 3D visualizations appearing so I press them H so they are invisible. After pressing the letter P the game has closed. upon return in .blend saves. I put as the textures appear again opening H. Then I pressed the letter P and the game is no longer closed.
I don’t know if it will help anything? more is the tip: Whenever to start the game press Alt +H
-sorry about my English-