Perhaps the most realistic game ever made, Half-Life 2 is full of eye candy, realistic physics, and smart AI.
The gameplay of Half-Life 2 is similair to most First-Person Shooters, but you will not see anything close to a cut scene in the entire game, the view is always through Gordon's (the main character) eyes and never do you see flashbacks or glimpses of things outside your field of vision. This, among many other things, makes the game more immersive and realistic. The game also sports a full physics engine, making the gameplay even more realistic by allowing Gordon to pick up, toss, drop, destroy and stack objects. The physics also apply to ragdolls of dead character models (e.g. headcrabs, combine soldiers, etc.). Valve added the weapon they programmed to test the physics into the game as the "Gravity Gun", which allows almost anything to be pushed, moved, flung, carried, or flipped. The game would not be nearly as impressive without the physics. The AI of Half-Life 2 is some of the best you will ever come across. They know their weapons, their environment, when to flank and when to hold their position. Combine soldiers and Resistance members know how to appropriatly use their weapons. For example, a person using a shotgun will try to get close using cover while a person with a pulse rifle will usually find cover and fire upon you from afar. Some AI (like headcrabs or zombies) where made intentionally to ignore the "fight or flight" programming, thus giving the impression of mindless and relentless killers. A skilled player can complete Half-Life 2 in around 11 hours of gameplay on the easiest setting. Though some of the more difficult chapters can be frustrating at times and usually they can take the player alot of time to figure out a solution to the puzzle and/or enemies.
The graphics in Half-Life 2 are superb, all character models look excellent and the environments look fantastic. The graphics are another thing that make Valve's shooter so immersive and realistically stunning. Everything just looks good, not as good as the PC version but still really good.
The sound in Half-Life 2 is another thing that makes the game so realistic. You can hear your footsteps on different surfaces vary (if you can hear anything above the roaring gun fire). The ambient noises are well done as well, you can hear distant fire fights and crows. The gun sounds sound as if your really firing a gun and how it would sound in the real world. The voice acting is superb and the music fits the game and is paced depending on which part of the game it is used in. Overall the sound is top notch.
The game is fairly cheap these days so the value is quite good.
Overall Half-Life 2 is a great addition to the collection of anyone with an XBOX, but not a top grade computer.