A
....and B. Certainly, you do realize it can't be as simple as that.
The best exemple for me is Final Fantasy: perfect franchise.
Changing course each time, but keeping the core element to drag the fanbase.
I've skipped some episodes I didn't liked, but each added its lot of innovation and plot twist, and half-hour summons.
Appart from that, the serie break into smaller fork, which expands the franchise in genre and in possibilities,
with titles like Chocobo Dungeons, Dirge of Cerberus, Crystal Chronicles and such.
Now, what we don't tend to see, is that games are softwares.
And in that regard, treated as well, with new episodes simply improving the formula,
while some others covertly serve the purpose of being a beta to a major title.
That being said, as an 'old-school' gamer, I'll obviously play games that have seen a certain amount of sequels over the years.
So inevitably, I'll tend to be both more conservative, and more inclined to expect innovation from said franchises.
Which, mind you, doesn't stop me from playing both the new Bionic Commando AND Final Fantasy VI at the same time.