Cocos2d-x is the cross-platform C++ version of the popular game engine Cocos2d. It's an excellent alternative to Sprite Kit if you want to write games that will also run on Android and other platforms besides iOS. It's well supported and used by many other devs. Guanghui Qu shows you how to create a simple game in Cocos2d-x that will run on both iOS and OS X, complete with monsters, weapons and physics.
Designing and developing a multiplayer game can be a lot of fun, but it can also be daunting. For example, how do you keep players' state up to date with each other and with the game? How do you minimize cheating? Gabriel Gambetta gives you a detailed 5-part walkthrough of multiplayer games that examines these issues and more. If you're considering developing a multiplayer game then you should read this first.
Wow! Microsoft has made some big moves towards openness and cross-platform compatibility recently, but this is big: you can now run your iOS apps on Windows 10 with ease. It's called Project Islandwood and it's a Windows-ObjectiveC bridge. It remains to be seen how Windows-compatible most iOS apps will be out of the box, but read on for an interesting summary and keep this one on your radar.