What a game. What a legacy. I'm sure you're already playing this gem near constantly, so it should be obvious how to get it. I'm surprised it isn't inate knowledge built into the human race by the grace of God by now, but we are each an imperfect being. On the off chance that you didn't pay full price for this masterpiece on release, and keep it running 24/7 like the rest of us, you simply need to download it through Steam. For such an honor you might think it necessary to perform some holy seance or reach some deep meditative state to achieve such levels of trancendence... but nope. Just download it.