These forums are F*****G dead man! Oh well, lets see since you two are talking Xenosaga, how about this, "Unfinished Business"
What are some game series that sequels were planned for but it never happened!
Advent Rising had a good story going, and thats about all it had, but the game that ended in a cliffhanger and the sequel never came through was freaking XIII, I loved the comic book style and the story was pretty good, the later stealth heavy levels really ruined the game though! and thus the game ends in a big reveal and we never got to play through what happened!