Oh its nice of you to remember me. I have played nearly all browser games and many downloadables. I am really really mentally tired :DD I have seen things you don't want to see :D
Anyways, I don't have the x-com but in the Unity mobile there is a refactor because Unity changed the ad API. And its in version 2020 so I guess there will be some more changes? I don't know I found the mobile coding a little bit tricking and out of my waters.
If you want to build a mobile game I believe its still relevant.
If you want the most value course though I suggest go with CodeMonkeys. I have his strategy course and its pretty legit.