Double the size of any previous Mass Effect downloadable add-on, Mass Effect 3: Omega is an enticing proposition, adding a hefty dollop of additional story to the trilogy closer, as Commander Shepard returns to fight for control of the eponymous Omega Station, as General Oleg Petrovsky mounts a Cerberus attack. That's the simple set-up for the next ME3 add-on, which returns to one of the key locations from Mass Effect 2.

Our hands-on demo is a sort of highlight reel of 20 minutes cherry-picked from the Omega DLC, with most of the chatty bits cut out of the game. Shame. The dialogue exchanges are some of our favourite moments in the Mass Effect series. Never mind. There's plenty of shooty action on offer then, as Shepard teams up with Asari gangster Aria T'Loak to tackle the Cerberus forces who are striving to deactivate Omega's shields, leaving it susceptible to asteroids and other space-based detritus. Your mission is to take back the station from General Petrovsky and Cerberus's clutches to save it from being bombarded into oblivion.

Shepard also teams up with new female Turian, Nyreen, as we begin the demo aboard Aria's ship on a crash course with the Omega Station. Our goal is to take down the Cerberus defence system on a part of Omega that's presumably situated in a different sector to the one visited in Mass Effect 2, with the lively Afterlife club, dark alleyways and seedy slums.

With Aria's ship creating a hole in the hull, we're able to leap into Omega all guns blazing, as Cerberus forces mount an attack. “This is what I need you for, Shepard,” remarks Aria, as we engage in an all-out ground assault against the usual Cerberus troops, Centurions, Combat Engineers, Guardians et al, before stumbling upon one of Mass Effect 3: Omega's new enemies, the Rampart mech.

A fast assault mech with red omni-blades, the Rampart can be lethal if it gets too close, so keeping them at bay with biotics and Shepard's arsenal is vital. Hemmed in by forcefields that are near-fatal to the touch, we have to rely on Aria's knowledge of Omega's hidden tunnels and shortcuts to bypass them, and it's in this next area that we meet Nyreen for the first time.

Stepping out of the shadows in a black hood, not dissimilar to Kasumi Goto's cloak, Nyreen looks to be a formidable addition to Shepard's squad, with a variety of biotic abilities at her disposal. Like Garrus she's something of a badass, able to hold her own against the Cerberus onslaught and the rapid Rampart mechs. We don't get to know much about her though, thanks to the stripped-out dialogue. Bah.

After a few incredibly short and truncated dialogue sections that give nothing away whatsoever, we find ourselves encountering a Cerberus patrol without being noticed. Launching an ambush, we target the Atlas mech to remove it from the equation as quickly as possible, before taking out the rest of the Cerberus reinforcements. It's a remarkably tough battle that throws a lot of Cerberus troops our way, as we're tasked with activating sentry cannons to help stave off the waves of attackers.

With friendly Vorcha and Batarian soldiers across a broken bridge helping out with some support fire, as we activate the cannons, we're soon able to overcome the Cerberus forces, before a cut-scene kicks in to show just how many troops we've managed to massacre. It's a lot. For now though, it's mission accomplished and the demo concludes.

Having only played a succession of firefights, it's hard to gauge how compelling Mass Effect 3: Omega will be in story terms. We know that Mass Effect 3 works fine as a cover shooter, but it would have been nice to see at least some of the narrative aspects at work in Omega. We know only a few small plot points that we've mentioned here, but that's about it. Yes, Mass Effect 3: Omega will be twice the size of any previous Mass Effect DLC, but whether the quality will match the breadth of what's on offer is uncertain based on such a short demo so light on story.

Banding together with Aria and newcomer Nyreen seems interesting enough though, so we'll be looking forward to playing Mass Effect 3: Omega when it launches later in the month.

Mass Effect 3: Omega is out on PlayStation Network soon (a PS3 date has yet to be revealed) for $14.99.