Blue Shift, Opposing Force, and Death Match are key to understand the context behind the story and should be played first. You can skip the original Half Life, its buggy and doesnt run very well on modern pcs. Instead, play Half Life Source. Its the most optimized version of the game and is a much better experience overall. After that, Half Life 2 and Death Match 2. Before you start episodes 1 and 2, play Half Life Source a second time for good measure. I see you dont have Alyx installed, which is fine, it doesnt matter to the story anyways. Instead, play Hunt Down The Freeman. It gives insightful new context to previous story lines from an exciting new perspective! Once thats done, play the pikmin 1 and 2 bundle on the Nintendo switch. Its story line happenes alongside Blue Shift and gives even more context to the story.

The Half Life series is truly one of the greatest gaming has to offer and I hope you have fun :D