Just small correction, cloud save works between mobile platforms (Android and iOS), if you can get it to work on latest iOS (or not update to latest iOS, there's some bug with iOS:
viewtopic.php?f=5&t=15958 or update to latest EK version to solve it).
But, in general, it is "one" game, it uses one type of save files and is completely exchangeable between all platforms, you only need to find how to move save file (EK.bak) between different devices.
After you move file, you need to import it (and export to move it to different device) to make it work.
Otherwise, it works great, but, there's one more caveat: Please make sure, just in case, you have same EK version on all devices you play EK on.