First-person mode is the big change. It's not just a case of plonking a new camera within a character's head, just because they could, but an extensive rework of the game's movement, driving and targeting engines. There are thousands of new animations for gun reloading alone, no to mention the first-person views of parachuting, carjacking etc.
A particularly fine moment is being run over by a speeding truck in first-person, watching the world rotate and blur, like tipping your head back on a rollercoaster. Peer down with the right stick and you can see your feet, your body and even your phone, now a full 3D object, not a 2D icon. Selfies have never looked more stupidly real, even if character's faces are still a fissure below the uncanny valley, with the ability to blush, raise eyebrows and other relative subtleties.
First-person options are bogglingly extensive, with options for Assisted Aim, Semi-Assisted Aim, Free Aim and much, much more. You can set first-person targeting with third-person cover, or third-person targeting with first-person driving... the choice is huge. First-person (FP) street brawls feel more hilariously, violently wrong than ever. The FP combat would even lend itself to a Punch Out-style dedicated mini-game, if Rockstar desired. That's the point: Rockstar, bizarrely, were in danger of becoming trapped in the open-world genre of their own creation, forever tied to third-person conventions.
The FP mode, at a head-dipping, momentum-fuelled step (yes, you can toggle this too) moves Rockstar into the most lucrative arena outside their own: the first-person shooter. Battlefield Hardline might be a first-person cops 'n robbers squad shooter that apes GTA, but Rockstar's game *is* GTA, now liberated to tackle any genre it chooses.
GTA Online lets you create FP-only races and death-matches, with the long-anticipated Heists now, apparently, on the near-horizon. Call of Duty-style contests? Almost certainly, and Rockstar have the scope to tackle their rivals on all fronts with custom DLC and user-created FP content.
