Random observation, for what little it’s worth - I find it slightly amusing how on playing through BM I realised what had been a near-future setting back when I first played HL was now ‘alternative history’.
I presume the devs were quite concious of this when making it. Its all those bulky CRT monitors and beige boxes with 8-speed CDROM drives, mainly! And no mobile/cell phones either!
Presumably these signifiers of a period setting will become more numerous as time passes and fashions and technology change - look at those out-moded MP5s! Why did men in those days all have to wear those ridiculous ties? Teleportation doesn’t work like that! Etc.
Mostly the age of computer games is indicated by their technical limitations, but I guess as with movies, it will soon start showing up in a more in-universe way.
(I note that the Lambda complex actually had flat panel monitors - bigger budgets there, I guess?)