It forever changed: First-person interaction, narrative and physics-based combat. Although you can easily point to Goldeneye as the game that helped instil a love of all things first-person to an entire generation, it was with Half-Life 2 that Valve really started to experiment with the best the genre could offer. By thinking of the first-person element as more of a defined perspective for interacting with the world, Gordon Freeman's second foray into tackling the varying horrors within, helped bring to life a character that would otherwise almost certainly have been reconciled to the bland books for all eternity. It's a testament to just how enjoyable exploring the world of City 17 (and beyond) really was, and just how engaged and purposeful every step you took felt, that thousands of players pretty much forgot that protagonist Gordon Freeman was mute - instead embodying his struggle against the machinelike Combine with a devout purpose. Not only did HL2 establish the very idea of playing out 'cutscenes' with you still able to walk around as characters talked and animated around you, but thanks to Valve's technical mastery they also let you fling any number of in-world assets around with the Gravity Gun. It's something Crackdown would capitalise on for the Xbox 360's launch, but never had it been so satisfying to just effortlessly pick up something like a car door and thwack an enemy goon with it. Simple pleasures.
