Like death and taxes, video game sequels are one of life's absolute certainties - though at the best of times, they're a good deal more enjoyable.
But the pressure that falls upon the developer of a successful game is unmistakable, to deliver a sequel that's at least as good as its predecessor if not significantly better.
And though the likes of Rockstar Games and Naughty Dog have constantly one-upped themselves with each new sequel release, the history of the medium is filled with sequels which botched their attempts to deliver a rich new experience.
While countless good-to-great sequels have basically just given fans more of the same, there's a clear desire by many developers to push the envelope and help move the series - if not the genre or even the art form itself - forward.
But that ambition - whether cynically motivated or not - often ends up falling flat, where a game forgets its beloved roots and in turn loses the sense of identity that brought it to the dance in the first place.
These 10 video game sequels all sought to make drastic changes to their established IP, but in turn just left fans questioning whey they even bothered...
10. Resident Evil 6
After Resident Evil 4 thoroughly revitalised the survival horror franchise with its over-the-shoulder combat and more expansive locations, Resident Evil 5 began pivoting the series further towards action while de-emphasising the horror aspect.
Resident Evil 6, then, saw Capcom commit fully to a new era for the franchise, where genuine atmosphere and terror was bafflingly scarce, replaced with comically over-the-top, Michael Bay-aping set-pieces that left little lasting impression.
Add to this a bloated single-player mode comprised of several over-extended mini-campaigns, and the result is game that simply strayed too far from the rejuvenating brilliance of RE4.
While Leon's campaign at least attempted to homage Resident Evil's earlier years, the game as a whole feels uneven and schizophrenic, and is in turn unlikely to fully satisfy either the action or horror crowds.
On the plus side, its divisiveness eventually led Capcom to give the series a soft-reboot with the brilliant Resident Evil 7, which by returning to its survival horror roots and radically unfolding from a first-person perspective, was a game-changer for the better.