Considering that the Half-Life
engine was built from id's original Quake engine, the final result is truly astonishing. Certainly one of the most impressive aspects of HL
is its skeletal animation system, which gives each main entity an extremely lifelike appearance using a structure of individually animated 'skeletons' to move every part of the model. When a scientist talks to you, you actually see his head turn as you walk around him, and his lips move with every syllable he speaks. Amazing stuff.
As mentioned before, the enemy AI is unpredictable, unprecedented, and totally unforgiving. I haven't seen computer-controlled opponents this cunning since, well, ever. Since you can bet that no battle will be exactly the same in HL, you can have some fun replaying the same scenes over and over, using different strategies each time.
Simply put, if you haven't played Half-Life yet, you're missing out on one of the greatest gaming achievements of our time. There's a reason why just about every gaming magazine in the world rated this one as 'Game of the Year,' you know. Get out and buy it now if you haven't already -- it's impossible not to fall in love with this game after playing it for five minutes.