The portal and the Citadel

[Loeka]

I think I might have figured the Half-Life story, but there is one remaining thing I don't understand: After the resonance cascade the Black Mesa facillity is destroyed. The portal is destroyed, too. The Citadel was build in the mean time, but why does the Citadel launch a portal and why does Breen want to enter it with that weird ball thing of his?

[Major Havoc]

Think of the Resonance Cascade as a crack in the universe that allowed a connection to the border world of Zen that is dominated by the Combine. The Combine were able to use those cracks in the universe to open their own portals using their own technology, thus bringing on the "Portal Storm" and defeating Earth in the "Seven Hour War".
Dr. Breen was trying to escape off world through using the Combine Portal

[Vaxivop]

Sisisspore eredeti hozzászólása:

The Citadel was build in the mean time, but why does the Citadel launch a portal and why does Breen want to enter it with that weird ball thing of his?

To bump it down: The Citadel is build between HL1 and 2, Gordon makes the Core destabilize and "melt down" in HL2.
In Episode 1 the Combines made a plan to explode the Core inside the Citadel to create a super portal that enables the Combine to launch a full scale attack.
In Episode 2 you fire a missile into that portal, destroying it and ending the Combine plan.