Several years ago PCG reported on the early stages of a project by programmer James Lambert, who really loves the N64 and decided for the hell of it to make a version of Portal that runs on hardware first released in 1996.
Well, Lambert is clearly the type of chap who commits to something and then follows through, because he's spent the time since then continually adding bits and bobs and now has something which, to my admittedly uneducated eyes, is the most impressive homebrew game I've ever seen.
Perhaps it helps if you had and loved the N64 as a child, because it is incredible how much of Portal this manages to capture, from the brilliant central mechanic itself to things like the object physics. And the lighting! The opening cutscene!
Hell, the fact that Lambert insists on playing this through an actual N64 rather than emulating the hardware. This is simply amazing work.
The first time we covered this, it was because Lambert had managed to get the portal gun itself working. Several years on, he's added… well, he's added almost everything that is in Portal, from Chell to the voice acting to the flickering chamber signs to the menacing orange glow you can sometimes glimpse through the facility's cracks.
As you watch the video and see Lambert discuss how he's fixed the cube's physics issues when putting them through portals, mentioning that you see the lighting boundaries affecting its surface, it couldn't be clearer just what a labour of love this has become.
It is an incredible achievement, even if Lambert still has a laundry list of stuff to add and fix (including rumble pak support!), and the only downside is you'll need to mess about with a linux-based N64 emulation setup to get it running. Lambert's ongoing work can be followed on Youtube, the project is on GitHub, and if you like Nintendo 64 then boy does he have a treasure-trove of content for you: why not start with Skyrim (kinda) running on an N64.