Some cool game play videos. The 2nd and 3rd ones feature a lot of use of the gravity gun. These aren't HD videos.
Soldier and Helicopter Fights - 33 megabytes
http://streamingmovies.gamespy.com/x...mvhighwide.wmv
Kill the Copter - 39 megabytes.
http://streamingmovies.gamespy.com/x...mvhighwide.wmv
Driving, Mini Tri-pods, Big Tri-Pods - 70 megabytes.
http://streamingmovies.gamespy.com/x...mvhighwide.wmv