HL1 was great. The critical differences between HL1 and HL2 from my perspective:
The enemies
In HL1 the army's special forces posed a real threat and they acted accordingly ('nade flushing then advancing etc.) and made you act accordingly (either run away or adapt to their tactics).
In HL2 every single opponent is just cannon fodder with a different gas mask on.
Note to you aspiring FPS game developers: If you pussify your game via removing any chance of death, the end result is your game becomes boring as shit.
The setting In HL1 you were between rock and a hard place. The others couldn't give a crap about you and you just did your best to escape.
In HL2 the world revolves around you and everyone's waiting for your move to save the world. Considering no opponent causes any real threat, so saving the world became a nice stroll around the park.
I will give you time-out. When you have finally changed your opinion, report back to me. If you do not do this, I will spam your email by sending erotic pictures of Gabe Newell. Needless to say, I have lots of 'em. Specifically three gigabytes.
I must say I see Spankmeyer's point of view, and it has it's right to exist... but I do not agree to his judgement since I really believe he's paying attention to the wrong aspects of the game