I'm after the name of an old space sim game I had on a shareware-filled CD-ROM that came with a new computer with old games on it such as Wolfenstein, Jill of the Jungle, Lemmings, etc.

What I remember from the game:
At the start of the game you play as a human but halfway through you defect to the side of the alien races.
I remember there are Blue and Purple Ships on the Alien side, The humans had some scorpion looking ship as well. I think I remember some ships being called the Liberator and the Interceptor.

It's not much to go on, but it's definitely from the 90's. Pic is not related, sadly.