I figure there are plenty of these. There are many games with stories that basically died because the production company was bought out, or went bankrupt.
I'm trying to only mention series that do not have a sequel either officially announced or under production.
-Deux Ex (sequel, not the forthcoming prequel)
-Freespace
-X-Wing/TIE Fighter/X-Wing Alliance series (basically do a re-imagining with next gen graphics and a new story, or find a way to tie the story into Star Wars mythos like the others did)
-Portal (coming at some point, but who knows when...)
I'm trying to only mention series that do not have a sequel either officially announced or under production.
-Deux Ex (sequel, not the forthcoming prequel)
-Freespace
-X-Wing/TIE Fighter/X-Wing Alliance series (basically do a re-imagining with next gen graphics and a new story, or find a way to tie the story into Star Wars mythos like the others did)
-Portal (coming at some point, but who knows when...)