Halo 4 might be the most accomplished franchise update I've played. It's a Halo game through and through, but pause for thought and you'll realise that it's also a complete overhaul - every nut and bolt has been teased out, tinkered with and screwed back in.
Here are seven of the bigger alterations that struck me when I finally sat down with the campaign last week. For details of changes to multiplayer, check out this piece on why Halo 4 isn't the online shooter you remember.
1. The environments are a cut above
Halo: Reach was a little bit staid on the scenery front. That's principally Reach's fault - a garden world in the organically grown vein, it couldn't hope to rival the free-wheeling techno-grandiosity of a Forerunner installation, and much as we enjoyed assailing that Covenant cruiser, we've assailed Covenant cruisers before. By contrast, Halo 4's environments will block your socks straight out the airlock. This is a game that begins on a ship chopped in half, with one early firefight taking place on the hull itself while enemy ships jockey for position overhead. That's before you've even set foot on - or rather, within - Requiem, a Forerunner Dyson sphere housing fauna and flora thought obliterated alongside the Flood tens of thousands of years ago.
At one point, Chief and Cortana must access a beacon housed on a floating central platform by beaming around and about an enormous archipelago of floating purple rock. Veins of magma spider-web across beautifully arid sweeps of crystal, and the Forerunner installations themselves resemble a Tron spin on Aztec decor. Classy stuff.
2. The Grunts are different
I'm a big fan of the Grunts. Perhaps their biggest fan. For nasal, unstable frog creatures who are dangerously well-equipped in the explosive department, they're oddly charming - and they're the most obvious component of Halo's tried and tested AI sandbox, ebbing and surging around the theatre of war as you pick off their commanders, flank positions and generally, you know, terrorise them with your butt-kicking prowess.
I'm not entirely sure how I feel about Halo 4's Grunts. As with character models across the board, they're a lot more detailed and better-lit, and they now speak a fizzy, deliberately ill-compressed form of Gruntese - one among many subtly worthwhile departures from the Bungie formula. On the other hand, I'm not so fond of how they move, or rather how they don't move. The new Grunts seem more stationary, less reactive than their predecessors, though this could simply reflect tighter environmental constraints earlier in the game.