Half Life 2 is nothing short of a brilliant first person shooter that has no map or radar to guide you to your next destination nor does it ever try to hold your hand and make you get a grip of the game. It just pushes you into a dangerous territory and an arduous and long journey that not for a second feels repetitive.
Half Life 2's AI is also very good and they aim as well as you might. As Gordon Freeman, you continue 20 years after the events of Half Life 1. I never paid much attention to the story line as you basically get engrossed in saving your skin and fighting through the human & mutant forces. This is a classic game that relies on health packs for health and not the regeneration of health as in the new games these days. The game gets incredibly difficult at certain points even on normal difficulty. You find yourself surrounded by enemies of various types in small quarters with whom who you have to use different weapons to deal with them and at the same time you are constantly on the move and your aiming has to be very precise.
The gravity gun is a great concept introduced by Half Life 2. Especially the super gravity gun that you get for the last 2 levels in incredibly fun & allows you to push & pull human AI's and just about anything and smash them into the walls. Kind of reminds of the force push & pull powers in the star wars games. Half Life 2's levels are long & the game lasts a decent 24 hour for the single player campaign. The levels are designed very thoughtfully. The environmental puzzles you come across are very logical and require rational thinking. Wood floats on water & crates smash when struck on solid surfaces. The physics are very well done.
Half Life 2 makes you work very hard in some cases & the satisfaction of beating the game is superb. It's not an easy ride like the CoD campaigns you play through & the boss fights are tough as well.
For example, I had to leave the buggy I was driving due to a force field that was activated out there. I traversed on foot and traveled 20 minutes fighting enemies and gunships to activate a switch that the game makes you guess was for the force field. I traveled back all the way from my detour to find the force field gone and had to continue on my buggy. Some detours like this makes you feel that you are actually on the right track and confuses you as to what the switch was for since its been a good 20 minutes since you left the force field.
Easily the best shooter out there with a long enough game play campaign to satisfy you. The story line is top notch and delivered via talks. There is no objective screen or as to what you have to do. It's very practical & you have to guess it.
If you haven't played it already, you are missing one of the best FPS of all times.