Half Life 2 was released in 2004, 6 years after the first one. As i said Half Life revolutionized the FPS genre. Both story wise and gameplay wise. They were the first to do what others dared not to. And guess what? They done it again with it's sequal.
Half Life 2's budget consisted out of $40,000,000. What's revolutionary about this game is the source engine. It provided realistic physics and facial animations.
In the first game a portal opens up from a planet named Xen. You end up destroying the Queen, thus braking the portal link and ending up in captivity of Gman. The events of Half Life 2 happen 20 years after Half Life 1, somewhere in a eastern Europe town called City 17. Human race got enslaved by Combine, an alien race that was in war with Xen, which got interested in Earth after the events of Half Life 1. Gman decides to send you to City 17 to help the resistance.
The realistic facial animations, and graphics in general that source engine provided really add up to the experience. The character really come to life thanks to those facial animations. The game was also filled with action packed cinematic set pieces, as well as unique levels. A zombie town for example. Or a land with arachnid creatures coming out of the sand. The boat chase. Or the one where you have to use the crane to get you car to the other side of the gate. And that final level. Once again, there was no game like it. They were the first to do it.
Back then COD didn't have nukes. There was no David Cage's Fahrenheit/Heavy Rain, or Naughty Dogs's Uncharted/Last of Us. No Telltale's Walking Dead or L.A. Noire. So "Bravo!" to Valve.
Thanks to the physics that source provided, the new thing about this game is the gravity gun, which lets you pick up and throw objects. You can pick up sharp objects and cut enemies in half. Or use explosive barrels to lite them up. Or simply smash them with something heavy. Or say to throw back a grenade.
There are also new enemy types. New headscarb types were added. There are ones that are poisonois. When encountering a zombie like that, he will have like ~5 of them on his back and will be throwing them at you. They also make a very scary noise. And there are also fast ones. The zombie versions run ... very fast.
There are also arachnid creatures. They look like the arachnids from Starship Troopers, but unlike them they can also leap. At one point in the game, you will be able to control them.
When you are not fighting these guys, you will be fighting the Combine, which use guns. There are also striders which are large 3 leg robots with machine guns. And small flying drones.
FInally, once again, there is plenty of puzzles to do here. Even more thanks to the physics that were added.
This game has 13 chapters, and lasts ~15 hrs.
This game also has huge mod library. And the community is still active. That's a great value for the amount of money you pay.