Ok, so last night I finished Half Life 1... And honestly, it didn't answer any of my questions about HL2
There really wasn't as much dialog as I thought there would be. I sorta got the ending with G-man, enough to understand what was going on. But unless I'm blind, I didn't find anything in the game about Dr. Breen (although I knew who he was anyway), I found nothing about the combine... Taking the game at face value only, the only thing the game really told me was you were part of an experiment gone wrong (perhaps rigged) and all of a sudden you're fighting baddies left and right trying to escape when you're attacked by the military, now you're trying to figure out what happened. You get further into the facility and realize they've been using the portals to trap and study aliens. Then you make your way deeper into the facility and they tell you you have to go to the alien homeworld and kill the head alien. Then bam you're talking to g-man.
Maybe the expansions tell more? Because HL1 seemed to lack the cinematics and story i've read so much about. o_0