To answer your questions in order:
kennyPENTIUMpowers wrote on 2022-09-14, 14:29:
question : if you registered the shareware version back in Jan/feb/mar 1996 and paid some money did you have access to the full game?
No, you'd have to wait for the full release. I suppose you could draw a parallel with modern practice of pre-ordering games and Early Access.
kennyPENTIUMpowers wrote on 2022-09-14, 14:29:
or did the public have to wait 3 months for the full version? if so what was the point/advantage of registering the shareware version, come to think of it did the shareware version have to or offer a registration process?
The point is that you liked the shareware and now you basically bought the full game, lending some monetary support to developers in the meantime. You'd just have to wait for the full deal to get it.
Also don't forget that while you waited, you'd be playing the shareware game, possibly several times over, and that not even including multiplayer if one had access to it.
kennyPENTIUMpowers wrote on 2022-09-14, 14:29:
why would a company delay the release of the full version? was it that they hadnt finished making all the levels? was this a normal thing that went on back then? was this what happend with other games like Doom?
The developers did not "delay" anything. Once a stable, full-featured shareware build was complete, it was made available to the public. If you ever wondered why Apogee model shareware titles were split into episodes back then, this is exactly the reason: one episode could be showcased to the public, everything else was still being polished and updated by 3DR. Indeed, Duke3D shareware versions 1.0 and 1.1 are effectively pre-release builds, only that the differences from the final product is relatively minor.
Developers could get useful community feedback that way. If you ever wondered about mouselook in Duke3D, initially it had none, but this feature was suggested by several users in newsgroup discussions, inspired by The Terminator: Future Shock.
And you're right, Doom had a similar development history. There was no registered version that corresponds to the initial shareware release v1.0/0.99. This was a common practice, and a long while ago I even tried to catalogue these "pre-registered" shareware releases. I fancy that list is far from complete if you count less well-known titles.