New enemies and more explanation of what is going on in the series makes for a fun game.

Like always the Source engine is amazing. Now I have a faster computer so I am running it at the best but at a much higher resolution. It looks awesome! There also seem to be improved effects and some charater models in this expansion. There also is now an option that I don't remember in other Half-Life 2 games, you can add motion blur to make the camera movement smoother like most newer FPS games. It makes the game look super smooth and is more subtle then some games go it doesn't seem to be over blurry.