The story of Mass Effect is about more than Commander Shepard's race to save the galaxy from the threat of the Reapers. It's also about how BioWare's game has gone from an RPG with shooter elements to a third-person shooter with light RPG touches.
Mass Effect 2 told part of that tale, sweeping the stats under the carpet and letting the sheer spectacle of BioWare's dense sci-fi universe take centre stage. It also pushed the shooting to the fore, with a renewed emphasis on combat ensuring that the action did as much of the talking as Shepard and co.
The third instalment in the series completes that journey. Over the course of a triple-tiered E3 demonstration, it's hard to pic out those RPG elements through the bang and bluster of it all.
Mass Effect 3 plays, to all intents and purposes, like a straight-up third-person shooter. Good job it also plays like a well-polished third-person shooter, and that the game's combat looks strong enough to bear the weight currently being placed on it.
Shepard's now more agile and more robust, darting from cover to cover with a conviction that was previously lacking. Traversal is more fluid, its importance in combat highlighted by the small neon blue arrows that point the player towards the tactical options at hand.
Enemy AI rises to the occasion, out-flanking, using cover smartly and wising up to the fact that running headfirst into gunfire isn't the smartest tactic. Certain enemies demand the player exploits Shepard's increased agility; riot-shield sporting Guardians need to be outmanoeuvred and taken down with a shot to their back.
These improvements open up a whole new approach to Mass Effect's battles. The pitched, stilted fire fights of before are more open, with more options to be explored.
Shepard's newfound adeptness allows the scope of the stealth element to expand. This approach is complemented by the all-new Omni-Blade, a tool which delivers brutal close-range melee attacks.
The Omni-Blade heads up a focus on more involved combat. Guns are rawer, more powerful and much more aggressive, their violent recoil and noisy splutter providing an element of feedback that was absent from past Mass Effects. They've been properly fetishised too; a new granular customisation option allows new muzzles and magazines to be attached and swapped in and out of Shepard's arsenal.
There's even room for more fireworks as grenades make an appearance. Unlike the eccentric exploding hockey pucks of the first Mass Effect these frags behave in a more conventional manner, describing a curving arc when thrown by Shepard.
The grenade's return is welcome, although it's possible that another step towards traditional shooter territory means another step away from the RPG template. It's territory that's crowded and competitive, and some scenes see BioWare going toe-to-toe with the genre's best.
One on-rails, turret-based set piece features a towering Reaper looking like it's strayed in straight from Gears of War as it's hosed with gunfire. So does a Cerberus Atlas power suit placed at Shepard's disposal.
Such excesses can be excused, though, when the fate of the galaxy is hanging in the balance. Shepard is unlikely to be able to fight the Reapers off with harsh language alone. BioWare succeeds in placing its bombastic action on a fittingly grand scale: Earth, in its death throes as the Reapers invade, looks particularly impressive.
Here the cityscape is dense, the horizon stretching far and lined with tall, clinical skyscrapers. They're eclipsed by the Reaper ships, towering monstrosities which spit out laser beams as they tear through the sky.
A press of a button will snap the camera to critical set pieces, as BioWare wants to ensure players don't miss the lavish spectacle it's laid on. Which is fair enough; this is a vision pulled from War of the Worlds as seen through the studio's future-perfect filter, and the end result is brilliantly effective.
While Mass Effect may have drifted further and further towards shooter territory, the classic sci-fi setting has bedded in well. The third game's locations are rich with the influence of airbrushed pulp cover art. A Geth base is brooding and industrial, while the Salarian home world is a deep Martian red seen through wonderfully excessive lens flare.
Beneath the combat there's still BioWare's cause and effect dialogue and a story that is increasingly becoming the player's own. Choices made in the previous games will come to a head. Some seemingly insignificant ones will have extreme consequences.
This is shown in microcosm by one Earth-bound scene where Shepard comes across a child scurrying through air-vents in fear of the on-going invasion. Two dialogue options are offered: either get the child to come with you or tell them to flee.
Only the latter choice is explored in the E3 demo, with Shepard going on to fight alongside a seriously tooled-up Anderson as they try to flee the crumbling city.
Several minutes and many explosions later, the two make their escape. Shepard turns to survey the destruction and witnesses the child crawl onto a transport ship, only to then see it disintegrate under fire from a Reaper ship. It's explicitly sombre, a little melodramatic, and an interesting indication of this third instalment's darker tone.
With the game's release pushed back to March next year, it's likely Mass Effect 3's calmer moments will reveal themselves in due course. But for now it seems only right BioWare is bringing out the big guns as it prepares to conclude one of this generation's most successful series.