Graphics and Physics: Designed to Impress
Even though the specs and numbers can astonish, they cannot replace the actual impressions Half-Life 2 leaves in the player. Once you begin to play, you get absolutely immersed into this world, its atmosphere and obstacles on your way. The whole experience is absolutely fantastic, but some details are not.
The geometry, facial animation and textures are realized excellently: every face looks like real and, unlike in Doom 3, people do not have rectangular heads ;). The weapons, equipment and ammunition are all well worked out by the designers. The levels are huge, just like in Far Cry, and very detailed. However, some minor details are not quite perfect, like the coastline on certain levels. This does not affect the gameplay much, but all such details are made extremely accurately in Far Cry for example.
Physics is obviously a big thing in Half-Life 2: the environment is almost fully interactive and behaves like it would in reality. Unfortunately, you still cannot destroy buildings and thus leave a 100% enemy-free territory behind you.
Half-Life 2 is not a hard game to pass. There are no crowds of monsters running to kill you, in contrast to id’s Doom 3 and this is actually a good aspect of the game as you have time to stop and think. Still, there are enough enemies to keep the adventure interesting. On the other hand, if you really enjoyed the hard battles with the alien beasts in Doom 3 or the masses of soldiers and monsters in Far Cry, you may find Half-Life 2 a bit unexciting.
Note also that the game itself does not have any clearly defined levels, just like the original Half-Life. You are just traveling freely around the gaming world, instead.