I played Half Life 2 for a bit, then got tired of it and forgot about it for other things. John Sullivan's letter in the Feb 2005 PC Gamer sums it up nicely for me:
Every puzzle, every stop point in the game, has one solution. There's only one way to play the game, only one way to interact in any given circumstance. ... City 17 is unpopulated and unexplorable. NPCs are non-existent except for the indestructible main characters ... There's a lot to like or admire ... but beyond that, it's just a console railed shooter.Half Life 2 is a good rail shooter with superb art direction. But in the wake of games like Deus Ex or Far Cry it's hard for me to enjoy a game with no real player choice.