so you're using the term shareware to refer to an era and not software.
like i said. a definition i wasn't familiar with
and i meant duke3d when referring to three levels of the first episode in the demo version
The shereware is only a distribution method. consist in put "only the first episode" of the game on the internet (or BBS on this time) or give it away diskettes whit it. if you brougth the full version it they mailed to you on a generic box.
the full version are the 2-3, 2-5 or 2-6 episodes, but the first you could distribute without limits (and it can be distribute whiout limits).
Exemple of shareware.
Skunny, Biomenance, Wolfenstein 3d, Duke nukem 1,2,3D, Descent, Cosmo cosmic Adventure, Commander keen, Quake. Etc
This method has a limitation the shareware episode is so long, it contained about 8-9 levels commonly and is really boring finish those levels again when you registered the game, that's why they are divided the games into Episodes too. some games like decent or Quake allow you to add the following Episodes to your shareware, but was uncommoun.
otherwise the demo versions were not common at that time so most of them are considered Post-shareware era. the only ones that were distributed by this method during the era were Spear of Destiny, Gemstorm, Hexen, Planet Strike (which was the first retail Apogee) all these were the first retail too and had both forms of distribution.
so I do not think they are so wrong since most of shareware were divided into episodes and in games It was an era (of software distribution of course) Is not used anymore. only some softwares use it, but is really uncommoun today...