Portal 64 canceled to prevent Nintendo from targeting Valve or the developer

Portal 64 was a project developed by James Lambert, where he sought to adapt the original Portal game into a playable version for the Nintendo 64, managing to adapt the first half of it before he had to stop, as Valve contacted him and after discussing with their legal team, they had asked him to stop, mainly due to him using Libultra, a Software Development Kit (SDK) proprietary of Nintendo.

Valve had to stop the project preemptively because, as mentioned in the video, letting it continue or approving of it would have made them a target for Nintendo's legal team, and nobody has anything to gain from that.

Valve is very accepting of fan projects of their IPs, as has been the case for other big projects that used Portal 2 or Half-Life's IP, but James sees this as a separate case, first because it was going to be a complete remake of the original game, and second, because the game wouldn't be able to be distributed on Steam, so Valve has fewer reasons to let this project continue.

James also mentioned the possibility of porting Portal 64 to Libdragon to lower the risks, as it is an Open-Source SDK, which would add more work but also more possibilities, except that he will only consider it if he fully knows that there won't be any legal problems, which seems unlikely; for the time being, he mentioned that he is currently thinking on developing a new original game, which will be playable and distributable in both, PC, and Nintendo 64.