Still Good!
I have played through Half-Life 2 somewhere between 18 and 20 times now and I still get caught up in the story and feel the same level of immersion as when I first popped in the CD. The game just holds up brilliantly and is still the most unique of it's kind. The level of detail that was put into the level design, character AI, balance of difficulty, and especially the amazing story made it a significant achievement in gaming history. Half-Life 2 also had another great feature, and that was the inclusion of the top of the line physics engine provided by Havok. The level interaction between the player and the environment had never been seen before at the time that the game was released, and it is still some of the most realistic and fluid feeling experiences today. Overall, Half-Life 2 is a brilliant game that, just like it's predecessor, changed the face of gaming. It should be on every gamer's shelf by now.