Game publishers Square Enix and Feral Interactive are currently running a giveaway event, offering unlimited free copies of Tomb Raider (Windows, Mac & Linux) to anyone who wishes between March 20th and March 23-24 (depending on your location).

How to unlock Tomb Raider

All you need to do is to go to the Steam page to claim, own and add the game to your Steam library, before the giveaway event runs out on March 24 at 11PM CST or 9PM PDT or on March 24 at 6am UTC, or something around these lines (the time that applies to your time zone will be indicated on the Steam page).

How to unlock Tomb Raider GOY Edition (with DLCs)

All you need to do is to go to the Square Enix page to claim, own and add the game to your Steam library.
Offer ends Monday 3/23/2020 11:59PM PDT. Keys must be redeemed through Steam by 3/31/2020 12:00AM PDT.

About Tomb Raider (2013)

Tomb Raider explores the intense and gritty origin story of Lara Croft and her ascent from a young woman to a hardened survivor. Armed only with raw instincts and the ability to push beyond the limits of human endurance, Lara must fight to unravel the dark history of a forgotten island to escape its relentless hold. Download the Turning Point trailer to see the beginning of Lara’s epic adventure.