There a few layers to this one:

After defeating the Yor, I get the message that I have destroyed the Yor.  However, the victory screen does not show the box marked.  

After defeating the Drengin, and many congratulations, the victory screen does not show it complete.  

(In both cases, I'm sure there are none left... and there was the popup dialogue with the guy telling me they have been defeated.)

Here is the screen of the victory conditions:

Then, after completing the game, and seeing the victory popup screen and all... the "continue" button is cannot be clicked.  If I click on Main Menu, then I go to a credits screen.  (Steam does not mark this as winning the campaign).