У вашего броузера проблема в совместимости с HTML5
Enjoy the power of Raspberry Pi 3 B+ on A+
Pocket friendly compact retro gaming SBC
How to update your pi3b/+ stretch image to work on the new pi3a+ (courtesy: ETAPRIME)
Put your sd card into your pi3b and go into the terminal. Type:
sudo apt-get update && sudo apt-get -y upgrade
After that is done go into raspi-config and make these changes.
In advanced options
Memory split = 348
And in boot options make it
Auto login into console
Let it reboot an make sure it boots into emulationstation. Then turn it off and move the sd card to the pi3a+ and turn it on.
You might need to reset the WiFi country, I didn’t but others have.