I have only played the Half-Life 2 demo but still...
Half-Life 1 is the greatest game i currently own, puzzles was great, athmosphere was great, almost everything else is great... but the intro... sitting in the train for like 5min? that sucked... also i didn't like the "story"
best part of Half-life is it's modability... i think half-life wouldn't be so popular without the modding tools...
I don't except much about HL2... First chapter sucked... it was like a tutorial/technology showoff or something... btw. didn't valve already made a HL1 remake for source? better graphics and stuff?