> Tyrain

... Well, we do at least have OpenTyrian... (Edited to add; And OpenTyrian2000)

> Epic Pinball

Best I can find for Epic Pinball is an old thread on Pinball Fantasies [0] but I think it almost counts cause there was shared dev work between the two...

> Halloween Harry

TBH that one would be fairly interesting, especially compared to Duke Nukem 2 (Part of me thinks they might be similar/same engine)

> Jill of the Jungle

That one honestly WOULD be a fun one to look at... Best I can find is Xargon [1] but part of me always got a vibe that Xargon was some semi-upgraded Jill engine...

> Duke Nukem

TBH Duke Nukem '1' would not be that exciting to me. AFAIR it's mostly an adapted CK1-3 engine, letter-boxed with status window to make it easier to calc the redraw.

Duke Nukem 2, is far more interesting since it's a different, more powerful engine (VGA, digital audio support, but AFAIR only required a 286).

[0] - https://news.ycombinator.com/item?id=28667945

[1] - https://github.com/dos-games/vanilla-xargon