A kind of blindness and deafness sets in at E3; you're so busy dashing from meeting to meeting, wearing out your voice and wondering where the next bottle of water will come from that it's impossible to see the big picture.
You'll piece together a picture of the show from overheard fragments and half-conversations with colleagues - Watch_Dogs is amazing, Star Wars 1313 is running on Unreal, John Carmack has built a pair of Space Goggles, and Sony's spectacular show-ender was matched only by Microsoft's opener, Halo 4.
Cutting from live action straight into the game, 343 showed off their version of Bungie's Reach engine, rendering thick fog and dense jungle in a tightly-scripted sequence apparently designed to scare the living piss out of existing Halo fans. Instead of a wide-open Halo map this was a skinny corridor; instead of free-form combat this was scripted enemies attacking on demand, lunging at the camera and knocking the Chief to his back. It's a complaint 343 answered behind closed doors the following evening in downtown LA.
If you caught Microsoft's E3 demo you've seen as much of Halo 4's story as 343 are prepared to reveal. Master Chief gets eaten by a planet, the UNSC Infinity follows him inside, and somehow we're at war with the Covenant again so we'd better go shoot at some things.
Requiem is a Forerunner Shield World - an ancient construct built to protect the Forerunners from the firing of the Halo array some 100,000 years ago, and it seems to have worked as expected because an army of 100,000 year-old Promethean super soldiers are standing between the Chief and the wreck of the UNSC Infinity. Microsoft's stage demo offered a taste of what the Forerunners can do but it's only when you face them in the game you get a sense for how they rewrite Halo's rules.
Microsoft put controllers in hands at a wildly expensive late-night event where they showcased Halo 4's PVP multiplayer and one level from the game's episodic co-op campaign. Over the weeks following Halo 4's release 343 will release new Spartan Ops maps and missions which pick up where Halo's solo campaign leaves off. Every episode has its own cut scenes and dialogue, and every episode can be played alone or with three friends.
The demo level - The Cauldron - sends you onto the battlefield with your own custom loadout, transferable between PVP and co-op, with all-new armour abilities and weapons available from the very start. There's a new boost pack, X-ray vision, a riot shield of sorts, and a new Covenant needler-like rifle, only without the purple rain and explosive money shot. Sprinting is a standard feature, Reach's 'blooming' reticle returns, and the whole thing still feels like Halo despite the new developers behind the wheel and the enemies you'll face along the way.
The Cauldron begins before Infinity even touches down inside Requiem, with a four-man Spartan IV team leading an assault on the entrenched Covenant forces by Pelican dropship. As the three mile-long Infinity drops out of slipspace it rams through the Covenant capital ships and opens up its MAC guns on everything it can't park on. This particular Covenant fleet is manned by the surviving religious zealots - the Grunts and Elites who remained loyal to the Prophets even in the face of extinction.
For them Requiem is holy ground; for everyone else it's a misunderstood relic and weapon of mass destruction which threatens every living thing in the galaxy. Infinity's job is to reclaim the planet for someone less likely to unleash an invincible, immortal army on the Milky Way as the final act in a bonkers holy war.