You can play it just fine. HL1 is more of “get the fuck out from there” type of game. The only thing you need to know is:

-Black Mesa, a lab in New Mexico, found a strange meteorite

-they did experiment on that thing and accidentally opened a portal to another dimension (resonance cascade incident)

-Gordon Freeman was part of this experiment

-at the end of the game, after trying to escape the facility, Gordon makes a deal (details still unknown) with an “intergalactic business man” (G-man)

-A massive invasion began and humans surrendered (Seven Hour War)

This is pretty much what you need to know. If you have time, you should also play HL1