GoldenEye: Source is a total conversion mod of Half-Life 2 that premiered a few years ago. GoldenEye: Source is a community-based effort to remake the GoldenEye 007 classic on the Source Engine.
While Half-Life 2 is natively available for Linux and Valve has been pushing Linux gaming hard, GoldenEye: Source hasn't yet seen an official Linux port. Fortunately, that's been made easier by today's open-sourcing of the HL2 mod. GoldenEye: Source is currently based on Steam's SDK 2013 release and the upstream developers of this N64 game remake have decided to open-source their work. While the lead developer will accept new capabilities added to the game, he isn't accepting features or other major code overhauls from the community at this time, "It is still in a pretty rough state since porting over to SDK 2013. There is a lot of work to be done still, but there it is. I will accept pull requests for capability and bug fixes, but not for added features or major revisions of code. Please use GitHub's issue tracker for any known issues you would like to see resolved."
The code to GoldenEye: Source is available via GitHub.com.
Here's to hoping that GoldenEye: Source will get a Linux port soon enough!