For example, this guy does a lot of code reviews for open sourced games/game engines: http://fabiensanglard.net. He has a very good code review of DOOM on iPhone: http://fabiensanglard.net/doomIphone/index.php.
Particularly insightful blogs on how to architect modern mobile apps (even if it is closed source) are also welcomed. For example Dropbox's tech blog on how they structured the code for their photos app: https://tech.dropbox.com/2014/04/building-carousel-part-i-how-we-made-our-networked-mobile-app-feel-fast-and-local/