Installing game with gold

As StuartATrueRed stated you do not need gold to install games, however I will add on to what he said. You do need Gold to play any games you got, not to install only play, from the Games With Gold program.

You will need a xbox live subscription but you do not need Gold to install games. However, you may require a Gold subscription to play the games you are installing.

Hi there EuanRawlings405,

Thanks for reaching out here in Xbox Forums. I understand there is an issue with redeeming the Xbox 360 game with gold -
Portal: Still Alive.

I recommend checking out the following troubleshoot article:
Troubleshoot Xbox 360
Marketplace purchasing.

• I'm getting the message "Your account is unable to make this type of purchase on Xbox.com. Please complete this transaction from your Xbox."
  • This error means that the Microsoft account that you're trying to use to make the purchase doesn't have the ability to make the purchase.
  • Child and teen accounts are prevented from making purchases in the Xbox 360 Marketplace. Changing your Microsoft account age or your purchase settings won't resolve this issue.

To resolve this issue, purchase or download the content on your Xbox 360 console.

Try this out and let us know the results.

For download X360 games on Xbox ONE from Games with Gold. You must have a credit card added to your MS account. Then you can download the game. If you still can't check your Xbox Live Gold membership. Check the status of your Xbox Live services. If everything
is fine then wait a few days and try again. Usually, the problem is global.

Do you have gold subscription dear sir? Maybe you trying with another account on your console?

Please, keep us posted.