VII is probably one of the worst offenders but then again I've come to the conclusion that SE doesn't really know how to make good sequels overall. KH is probably one of the few exceptions though I'm probably in the minority by being one of the few who actually likes the spin-off games much more than the actual numbered entries which are generally much more childish than the darker spin-offs.

Suikoden is one that I love and hate... On the one hand you can play most of the numbered entries and know what's going on but the novels/manga for the games bring so much more to the titles and Nash's awesome side story needs to be released outside of Japan cause they are hilarious and really awesome.

.Hack// was pretty awesome in the beginning but the lack luster anime series sequel to the games (not to be confused with the awesome prequel series) kinda killed my interest cause I felt the games ended everything quite beautifully. It's probably the reason why I have yet to play the GU series.

Xenosaga also tried this and is probably another terrible offender. Pied Pier which may be the best written entry in the series was left on Japanese Cell phones (thank god I found a fan translation), while the remake/retcon/abridged version of Episode I and II was left for Japan only despite the fact it changed a lot of things that gets referenced in Episode III and then they released a short set of web novels (Japan only) to explain all the events that happened between the year between Episode II and III and set up the third entries beginning. Seriously jumping to Episode II into II is quite jarring cause a lot of crap happens. Thank god the developers at least had the foresight to make sure all of it gets explained in Episode III but much of it is lost since its relegated to monologues or just reading Journal entries. It makes me sad some Xenosaga fans will never know how awesome Ziggy is and why Voyager is one of the biggest assholes in the series.

I guess the only thing I should be grateful for is that I wasn't as screwed by Monolith Soft with this franchise as the Europeans were "Guess what!? Were only going to release the crappy entry of the series in your country, you don't get the pretty awesome first episode, just a collection of its cutscenes (but that was what the NA critics said the game mostly was...) oh wait, you don't like the sequel cause its bad, well I guess we better not release the awesome third entry that actually makes up for Episode II with better gameplay, graphics, music, story and well everything really... Better luck next time."

Though Duke Nukem Forever will probably go down as one of the most costly and badly managed games of the 21st Century, I still feel Xenosaga should at least get the number two position.