The actors, I dare call them, in the game are amazingly lifelike, with faces and eyeballs that watch you (almost eerily), real facial expressions, and overall very lifelike movements and behavior. It really makes a difference. Normally game characters are stupid and just another part of the landscape, but here... it was different. I found my behavior was different towards them than in any other game to date. I would listen to them as they talked. I wouldn't go looting through their stuff or act like a jackass--at least, not so much while they were watching. I actually felt like I needed to act responsibly, because, well, they were other people. Very, very nicely done.
The graphics and scenery are top notch, everything around you is absolutely beautiful. I loved how bullets actually damaged the scenery and blood splatters would stick to walls. There was such a variety of highly-detailed landscapes, including city streets, sewers, beaches, long highway stretches, swamps, factories, prisons, and so many more. Great stuff.
The music is used sparingly, but is a great futuristic rock/techno score. The sparing use keeps it fresh, and heightens the adrenaline rush as you enter a new area or challenge.
What all of the above does is combine to give an amazing, engaging experience, that above all is fun. While Doom 3 uses cheap tactics to scare you, with monsters jumping out at you from the incessant darkness, HL2 gets your blood pumping the old-fashioned way: with good storytelling and great gameplay. 5 stars.
Here are some screenshots I took during the game:
Hey! That's my computer!