http://pc.ign.com/articles/717/717744p1.html
I will admit, that Elevator battle had me restarting a bunch of times. Either I would die, or Alyx would die right when the elevator came down.
Apparently, the elevator battle leading back up to City 17 was giving a lot of folks problems, and the update makes a few balance changes during the sequence. Specifically, more health has been added to the area, more cinderblocks and barrels have been added for use as gravity gun ammunition, extra shotgun shells have been added, and the number of zombies attacking the player has been reduced.
I will admit, that Elevator battle had me restarting a bunch of times. Either I would die, or Alyx would die right when the elevator came down.