1998. HALF-LIFE sends a shock through the game industry with its combination of pounding action and continuous, immersive storytelling. Valve's debut title wins more than 50 game-of-the-year awards on its way to being named "Best PC Game Ever" by PC Gamer, and launches a franchise with more than eight million retail units sold...
If you start with the second one you won’t know what’s going on and feel like you’ve missed a bunch of important story.
This is how it felt after playing the first one as well. Half Life 2 is almost an unrelated game. The plots of the two barely line up.