This time I'm afraid yer partly correct
Those times may be behind us, but its consequences are still felt to this day
The point is, only the CD2 file works like that out of the bunch (which is how I "found out" that the said dump of disc 2 is "inferior" & doesn't fit with others ) - the other two image files, Install & Play, refused to mount AND open (tried PowerISO, UltraISO, VirtualDVD, & gBurner; none succeeded)
The properties of those files are weird - non-Unicode letters in their internal image-names, possible password-protection (although not really, dunno what's the deal with it existing in the first place
), & various other flags that I haven't paid closer attention to (but it seems that none of those prevent the images from being convertible to ISO). Which leads to a possible conclusion that developers upgraded their format with features that are pretty much usable only on CDSpace, & due to a lack of proper changelog that such changes haven't been picked up (or even known) by other third-party programs
So yeah, the flagship atrocity seems to now be the only viable method of achieving the proper results that may, or may not, even exist (even though the converted ISOs already work better than the provided full demo, the results will still be worth the hassle, fer preservation sake)
Windows is shutting down