Humble Store free game: Killing floor.

[Elixer]

https://www.humblebundle.com/store/killing-floor

You got 1 day, 21 hours, 51 mins left to get this game

 

[Replay]

One of the few games that offers offline LAN play from one account, can host with your own dedicated servers, and use custom fan created maps.

Log in to a Humble Bundle account, link Steam account, do not select "Gift" purchase, validate browser, fetch key, redeem key before July 1st.
PITA, but only takes a minute or two.