Prologues/preludes like these pages are generally demos, and shouldn't get their own PCGW articles:
https://www.pcgamingwiki.com/w/index.php?title=Karagon:_Prelude&redirect=no https://www.pcgamingwiki.com/w/index.php?title=Project_Wunderwaffe:_Prologue&redirect=no
They can be mentioned as demos or free trials under the "Availability" section in the main game's article, as shown in the sample article.