Brood War intro movie confusion

[Exonerate]

Is this really how the story ends? with Kerrigan conquering everyone and the galaxy is doomed?

According to the secret mission, Duran isn't who he seems to be. I think he's Xel'Naga? There's experiments, including a Protoss/Zerg hybrid. I think they're meant to be the perfect experiment...
Edit: Sorry, I put ending mission instead of secret mission.

Eh, you misquoted me slightly. That was FaxModem1

Gah, my apologies. I took apart another post, but seem to have made a mistake with the tags.