Generally speaking, whenever a gaming platform has peaked in popularity and stepped a few paces back, to allow its successor to stand directly under the spotlight, that's when the real fun begins.
Because that's when its most dedicated and talented supporters, those who are produce members of the homebrew scene, come into play.
They make sure whatever gaming system has new games to come, well past to the point in which official support has been dropped.
Case in point, a just unveiled port of Portal for the Nintendo DS:
According to its creator, via Kotaku:
"This is still extremely early footage so please don't be too harsh… Lots of debug features are present, including the ability to fly, see portals through walls and move cubes from a distance. Also, keep in mind this was shot in an emulator which provides good but still less than perfect rendering. As such, be aware that most (not all, but still) of the graphical glitches you can see in this video don't happen on hardware (mostly the portal transition is a lot nicer on an actual DS)."
The port was created after six months of work, and is described as not being anywhere near a playable stage. Yet, even with sound also being missing, once cannot help but be supremely impressed by such an effort.
All that being said, one cannot not help to also wonder what an official Portal port would be like. Specifically for the 3DS. And while they’re at it, both Half-Life 1 & 2. Not to be greedy or anything.