How do I obtain XCOM: Enemy Within?
How you obtain XCOM: Enemy Within depends on whether you bought XCOM: Enemy Unknown from Steam, the Mac App Store, or another download store (including the Feral Store).
Steam
You can purchase XCOM: Enemy Within from the Steam store via this link:
To purchase XCOM: Enemy Within, follow the on-screen instructions.
Mac App Store
In order to purchase this additional content, please update to the latest version of XCOM: Enemy Unknown.
Double-click on the XCOM: Enemy Unknown Application icon while holding down the Command (⌘) key. The XCOM: Enemy Unknown pre-game Options window will appear.
Select the DLC tab.
Click the Buy in the Mac App Store button next to XCOM: Enemy Within.
Follow the on-screen instructions to complete your purchase.
XCOM: Enemy Within will now be enabled in your copy of XCOM: Enemy Unknown.
Feral Store and other download stores
In order to purchase this additional content, please update to the latest version of XCOM: Enemy Unknown.
Double-click on the XCOM: Enemy Unknown Application icon while holding down the Command (⌘) key. The XCOM: Enemy Unknown pre-game Options window will appear.
Select the DLC tab.
Click the View in the Feral Store button next to XCOM: Enemy Within.*
You will be taken to the Feral Store page for XCOM: Enemy Within. Once you have purchased it, you will receive a DLC key in an e-mail.
Click on the Activate my DLC button in the DLC tab.
Enter your DLC key into the six empty boxes.
Click the Activate Online... button.
A dialog box will appear confirming that your DLC has been activated and that you will need to download and install it before you can play. Click the Download button.
A progress bar will appear in the DLC tab that indicates how long the download and installation process will take. Once it has finished, a dialog box will appear informing you that you have successfully installed XCOM: Enemy Within. Click the OK button. XCOM: Enemy Within will now be enabled in your copy of XCOM: Enemy Unknown.
*If you wish to purchase DLC from an alternative download store, you can do so and resume the instructions from point 5.