othmanal . Based on my experience making Construct 2 games is that 1280px x 720px will be a great resolution for the future. 720px is playable and acceptable in high specs for example Apple Products and PC's but for Android, it is only playable in Android 4.4 and above depending in the game design. This is because the bigger the resolution of your game, the bigger your images are.
But that is only one part of the factor.
Another one is the Mobile GPU capability. A Phone might be new or is the latest android version or has a high cpu spec but if it's capability to render videos is only limited to 640x360 then your game performance will be a disaster in that phone. The reason is that the resolution of your game is higher than the specs of your phone and the images are also bigger than the resolution of the phone. Then the phone's Cpu will be rendering it all in compensation called Software rendering, and fps will surely drop below 30 (if lucky), below 10 more likely. Either way is bad.
Summary:
1280px * 720px will be acceptable if you publish only for Apple Products or PC's and etc but certainly "Not Android". Actually it is still playable and good performance in Android 4.4 (Kitkat) and above if it is high in specs.
But the Safe bet will be 854px & 480px: You won't be having problem in your optimized game even in Android 4.2
Safest bet: 640x360. This is actually recommended more for Pixel Games only. But assurance that it will work even on Android 4.0 devices.
1980px x 1080px : Trust me don't try it. It will be very hard even for Apple Products and Android Phones can't render 1080px games without fps drop.
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Based on your needs to work on Apple Devices and Android Devices :
I recommend : 854px & 480px