Nintendo's lawyers are not happy with the PC port of Nintendo 64 classic, Super Mario 64, and have been trying to get it taken down from the internet. While they are unlikely to be entirely successful, if you want an official version of the game, grab it while you can, because it may not be around for long.
The Super Mario 64 port was so special because it wasn't an emulated version as we've seen multiple times from elsewhere before. Instead, it was a complete port with support for DirectX 12, 4K resolution, widescreen monitors, modern controllers, and much more. This was the first time Mario 64 had been entirely playable on Windows 10 PCs with very little difficulty. It was a huge achievement and helped cement the legacy of one of the greatest platformers ever made, even more so.
But as is typical of massive corporations, Nintendo wasn't happy about this and has had its legal departments trying to take it down.
At least for now, their focus has been on sites hosting and distributing the files, rather than the creator, which may mean a version of this game will always exist at the source, but that may not be the case forever. If you want to get a hold of this now limited version of Mario 64, we'd suggest downloading when you can. It may not last long.