If I sideload the APK will the game run like crap and will I be able to load my previous progress?
I just checked RR3 at the Play Store through my PC.It say the game is not compatible with my N5 or my former Galaxy Note 2. Only my Nexus 10 seems to be compatible, which is where I used to play it.
However, if I filter the reviews section to show only the N5-related reviews, apparently a lot of people are able to run the game fine. And the reviews have been posted recently.