Call in. A single player mod which plays out at the same time as Gordon and Alyx flees the citadel in Ep1. You take the role of a rebel soldier on a mission to retrieve information regarding the super portal to aid in the building of Dr. Magnussons rocket.
The beach! don't swim to far out though. Leeches.
What a Beauty :)
If you could code an icthyosaur into this, it would make my day :D