I in 2008 had an image of Civilization IV (yes, now it lies somewhere at home, I will find if I should), which weighed about 150MB, when mounted in the demon it opened as a full DVD 4+GB, the game went with all the video inserts and other shell... how it was done I still don’t know

is very simple. The technology has long been known. It is called "pisset - not a bag to wrap".