Once again a solid review. Though I must point out that Dr. Magnusson was indeed in HL1. He even makes a comment about Gordon destroying his Casserole at the Black Mesa facility (which you could actually do in the very first part of the original game). Albeit, he did have a very small role in the first game, he was indeed there.
Also I think that Episode 2, was a good two hours longer than Episode 1. But I completely agree that Valve needs to get cracking on releasing their episodic content much more frequently.
TF2 is getting the most of my time and I'm not even a fan of online gaming.
Oh and Portal is the most unique, fun, and funny game I've played in years. I had the credits song "Still Alive" stuck in my head for days after I beat it.