They had to get pretty drastic with the code scalpel, though, cutting out the main thing that gives Windows its name: Goodbye GUI and hello to a text-only Win11.
News of NTDEV's achievement was posted on X a few days ago, though it's not something you'll be able to play around with, unfortunately.
If you check out the video of it in action, you'd be forgiven in thinking that this is just the command prompt in regular Windows, albeit running slower than an asthmatic ant with a heavy load of shopping.
The clue that it's not is when it shows all of the folders and files in the installation taking up 1.78GB of the C: drive's space. A typical Windows 11 install is typically around the 25 to 30GB mark, and while a good chunk of that is the default programs and tools, the only way you can get it that small is by chopping out some essential parts.
Specifically, what's gone is the graphical user interface (GUI), the software that generates all of the windows, icons, and associated actions.
It is an extensional crisis to have Windows without Windows. It also means that none of your regular programs and games will run because they require a GUI and related bits to function.
But it is Windows or, instead, the main body of code that lies underneath all the visual stuff when using your PC. Mind you, from the speed of it all in the video, it's nothing you'd ever want to operate daily.
That was never the intention of the project, though, and you have to admire the determination of NTDEV to keep pushing the boundaries as to how small you can make Windows and still have a functional operating system left behind.