Ignoring the countless design and interaction elements at play, one of the more unique aspects of video game franchises is their tendency to improve over time. Turn to book or movie series' and more often than not, there is a general apprehension among fans - concern that future instalments will not equal the first. More of the story may be told sure, but viewer bias tells us the sequels lack that initial hook - and so our opinion of them drops, almost always favouring that first experience. But things are different with games. Largely thanks to their compartmentalised nature - each instalment usually standing on its own two feet rather than directly relying on its predecessors - games are expected to and typically do improve with age. Assassin's Creed IV for example is a greatly refined, polished and distinctly pirate-y form of the repetitive and messy affairs of original character Altair. The recent release of Bayonetta 2 has shown just how much good time to simmer has done the titular witch, Borderlands 2 amounted to a more diverse and well-realised take on Pandora, and even the Legend of Grimrock 2 has taken its profoundly retro formula - very literally in many instances - into the light of modern gaming. From Persona and Disgaea to Uncharted and Halo, games frequently age well. Sequels are able to innovate rather than iterate, all without sacrificing their core values. This is not always the case, mind. That cycle is only sustained by new ideas and improvements. Once studios are fresh out of those and just start tacking numbers onto a tired IP, things become problematic.