Shadow Warrior: Special Edition is currently free on Humble Bundle. It can only be claimed for a little more than 1 day (24 hours) from now on. So hurry!
Grab it here.
To get it, login to your Humble Store account. Then add it to your cart and click "Checkout". There you need to click on the blue "Get it for free!". And after a few simple steps it's done!
You must activate the Steam key you claim before 10AM PT on August 5, 2017. After activating the key on your Steam account, it'll be added to your library for ever.