Yes the balls did kill the last stryder! I just kept running around, ignoring the men just in front of me and blasted the balls at the Stryder. It soon dropped then I could safely kill of the remaining men.
Some of the effects in this level looked very good. Sometimes I just kept picking up the people with the gravity gun and swinging them around in the corridors,
Loved the sound effects, also just kept tossing people high into the air and watching them come down and thumping onto the ground. And the bubble thing, where you could throw someone into it and they would float about, sort of slow motion effect, this looked quite good!