Star Windows Phone developer Rudy Huyn has recently posted on his blog that Microsoft effort to bring Android apps to Windows Phone would be sufficient to bring basic apps to the platform, but that the more useful and complex apps would still require dedicated Windows developers.
Having watched the 44 minute BUILD presentation of Project Astoria it is unfortunately and predictably clear that Rudy is mostly right, at least for now, and this is most apparent in the Q&A section, where when developers asked specific questions regarding support for specific Android APIs which would allow them to port their apps the answers were more often no than yes.
Specific examples include lack of support for low level Bluetooth access, which would for example not allow even Selfie stick apps to work easily, and current support for Background Audio, meaning a music app would not be viable as a simple port.
While it is clear from the presentation that the Android APK is actually running on your Windows Phone, with Microsoft emulating an Android KitKat API level, at present that API surface is full of big holes which Microsoft will be looking to fill over the next months.
See the video embedded above , and note at the 3 minute mark the presenter says many Android apps will work with little to no modification via Microsoft’s interop layer, which will automatically translate Android calls to Windows kernel calls, and note at minute 17 how developers upload APKs, not APX files, to the Windows Store.