App no longer listed, lost after transfer.

So I had a game in my old phone, Conquist 2 LE. After I bought my new phone, I backed up the old one in my PC and configured the new one with that back up. I noticed that the apps were not stored in the pc, as I could see them being downloaded when I opened the new phone. That game is no longer listed in the App Store. But it works in my old phone. Is there a way to transfer it to the new one?