Clark Davies, a designer from Sony Computer Entertainment Europe, categorizes game series into three sets: 99-percenters (games that don't change much, like Guitar Hero), Sea Changers (sequels that reinvent series' notions, like Final Fantasy XII), and Evolvers (games that build on their fundamentals, like Grand Theft Auto and Halo).
Davies considers Wipeout an Evolver, and for Wipeout Pulse on PSP, the biggest evolutionary goals were to improve accessibility and to empower the player. Pulse improved accessibility through a structured single-player campaign and freely selectable A.I. difficulty -- and, as the developers found through focus tests, the game's "Zone" mode became an emergent tutorial; it forced players to focus solely on steering the game's hovercrafts rather than accelerating on top of steering.
But the bigger goal (and also the bigger hook) was player empowerment, and that started with using the PSP's hardware virtues by way of custom MP3 soundtracks and JPEG photo-taking -- plus "no-brainers" like autosaving and custom controls. From there, the player could personalize the game through the ship-skin editor and creating custom Grid campaigns, then furthering that in community resources like wipeout-game.com, which tracks player stats.
Davies concluded by repeating that innovation doesn't have to be driven by gameplay alone, and that developers can reach success via a combination of existing features (in Pulse's case, features uncommon to handhelds), and by attempting a player-centric philosophy -- racing games can accomplish that easily, and especially so in the case of Pulse.