My game crashes on specific devices

I built my game, I’ve noticed it crashing on a couple of devices.

One is a low-end device, Samsung Galaxy Fame S6810

The game starts, I can see my start menu, as soon as it is supposed to show a small intro video it always crashes. I’m wondering if it has something to do with the phone’s very small resolution (320 x 480), or its memory, since my game is 3D. Is there any way to diagnose the real reason?

The other case is about a ZTE Blade. I’ve made my game compatible with devices with Android 2.3 and above, as I can see here:

the phone supports android 2.2, but my friend has installed Cyanogenmod 2.3.7.
Is this the reason why my friend is getting a
“your device isnt compatible with this version”
message?

It depends on the assets and meshes used in your game.Hope you have taken care of the points mentioned in this link for performance optimization

The truth is that this is my first game, so although I did try to make it quite light in resources (by reducing draw calls and polys/verts) it is possible that I may have done something not 100% efficient.

I’ve tried installing my game to my low-end tablet though (Eken A90) which is having quite a hard time with a lot of other tasks (even browsing can be a pain in the a$$ somethimes), and it seems to be running fine. I consider a few glitches unimportant. So I was wondering if I could figure out somehow exactly what is causing the issue, with some form of debugging, even if I have to borrow my friend’s device and testing it while usb-connected to Unity.

I can provide a link to my game in Google Play for further testing, I don’t know if this is considered advertising and it’s against the rules of this forum.