(Updated on January 13, 2024) James has released a video on their YouTube channel about this topic and the online patching utility is gone from the web.
Portal 64—a Nintendo 64 port of Valve’s Portal, independently developed by James Lambert—appears to have been shut down. In a YouTube video released on January 13th, 2024, Lambert described a conversation where Valve requested an end to the project because Portal 64 was created with some of Nintendo’s proprietary development libraries:
Although the project page is no longer visible on GitHub, the online patching utility for it is still up as of the publishing of this article. If you own the PC, Mac, or Linux version on Steam and are interested in trying one of the most impressive homebrew projects I’ve seen in recent memory, now could very well be your last chance: To generate your own N64 ROM, simply point the patching utility to the “portal_pak_000.vpk” file that should be downloaded with your copy of Portal. Once this VPK is patched, you’ll have v0.15 of the homebrew, which is compatible with real hardware. (Update) This link went dead about a day after the article was published. RIP!
For more information about Portal 64, be sure to check out Modern Vintage Gamer’s terrific overview from a few months ago: