This reminds me of a time circa 2005 where "Sub OSes" were somewhat popular in the GameMaker community. Seems that given enough time someone will try to make an OS-like interface in a given game engine.
It was a great way to understand UI and usability paradigms beyond building game mechanics.
This definitely triggered some pleasant nostalgia for me.
I think there's a build of an older version of it on the YoYoGames archive. The archive didn't save the screenshots that the original website had, sadly.
I also spent a long time working on a very large update which I might have archived somewhere locally but never shared it online.
It was a great way to understand UI and usability paradigms beyond building game mechanics.
This definitely triggered some pleasant nostalgia for me.