During its BUILD conference, Microsoft announced that Windows 10 will support both iOS and Android code through a pair of new SDKs made available to developers, making it easier than ever to port an app from either competing platform to Windows 10. The move by Microsoft will help bridge the noticeable app gap for Windows Phone, but Microsoft's Kevin Gallo explains that this strategy is meant as a starting point, not a long term solution.
Windows 10 for mobiles will support Continuum, a scaling UI design that lays out your desktop/Start menu in a way that is optimized for the device running the OS and what it's connected to. Continuum is one of multiple features available for apps built natively for Windows 10, making ported apps at least somewhat limited in their functionality once successfully ported.
"Messaging apps and those that have deep integration into background tasks will probably have issues running." -Kevin Gallo
The Project Astoria SDK is the tool used to translate Android apps to run on Windows 10, and when apps are ported using this SDK, apps using deep-rooted Android services/features will face some difficulties when running on Windows 10. These limitations aren't intentional hurdles placed by Microsoft, they're speed bumps that exist because there isn't complete parity between Windows and Android platforms.
The tune is better for iOS apps getting the port to Windows 10. Continuum will still be forfeited for an iOS app port but many of the deeper services integration are expected to play better with Windows services. What is being called the Project Islandwood SDK will give iOS developers more options when bringing an app to Windows 10, even the ability to publish the app for multiple Windows 10 stores (mobile, PC, Xbox and tablet) - a benefit that will be missed for Android ports.
“The user experience [of an app designed for a small device] will work on the desktop but it won't be decent across the spectrum." -Kevin Gallo
Kevin Gallo told TechRadar that the decision to enable app porting was meant as a cost-savings initiative to entice developers to Windows 10, and that porting apps "may not be an effective experience" in the long run.