Mobile-Friendly

Responsive design. Possibility to zoom in on specific area. Handling the screen rotation.

I don't think there's a one size fits all checklist as each app/platform is different and it's not a binary thing. You may have some really mobile friendly aspects and some not so much. But generally try the platform on a mobile and if it's usable then that's a start. After that you could add all sorts from refining responsive layouts to detecting the device type and loading smaller images or other assets for potentially slower mobile network data speeds.