my hunch is that this was done in order to prevent people from getting games for way cheaper by the proxy of having a friend from another region give it to you.
still, i do find this stifling, since i struggled with this problem before as well.
i'd like to imagine that people who don't know about OP4 {and Blue Shift, to an extent.} are people who aren't really familiar with Half-Life either. i'd argue Decay is the most obscure of the official campaign expansions, since it officially only released on the PS2 port of HL1.
my personal fascination with the HL expansions is the fact they kinda influenced the modding scene by inspiring people to make numerous mods that are about "reliving the Black Mesa incident, but you are [INSERT PROTAGONIST HERE]."
there are slight caveats to that data. first of all, i actually have more time spent within Terraria, since i have about 144 hours recorded in tModLoader.
and second of all, i do estimate about 250 hours spent in Fallout: New Vegas as well. but since i own it on GOG and not Steam, i do not know for sure.
us Half-Life fans are eating good this month.
first, we get Project Borealis Prologue, and now HL2 update and the game going free to own for a limited time.
i am so going to enjoy checking the update out. and the documentary as well.
that's just a spring.