It has been revealed on <a href="https://store.xbox.com/en-GB/Xbox-One/Games/Rare-Replay/367297b7-c6a3-4496-83ad-cb70c52ce8cd#gameDetailsSection">Xbox.com<a> that you're going to need quite a bit of harddrive space if you plan on installing all the games included in Rare Replay on your Xbox One.
While you only need 11.38GB of space to install the basic game including all of the pre-Xbox 360 releases, the remaining games will take up 38GB more.
"After purchase, the Xbox 360 titles within Rare Replay will also be added to your download queue. Installation space for all titles will require a further 38Gb. If you cancel the installation of a title, you can reinstall at any time by locating the title in the "Ready to Install" section of My Games & app or within the Xbox Store."
A pretty neat solution saving you the headache of having to download all of the rather hefty Xbox 360 releases in one go.