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].”