Despite the nice touches, it's a slow start - just Shepard, in a room, walking slowly between objects of interest and pressing 'use'. The aim is to amass enough data to pinpoint the Leviathan's location on a galaxy map. Sightings of a strange alien, for instance, can be cross-checked with migration habits of Rachni to narrow the search. Once you have a clutch of potential planets, it's off to your ship to travel the galaxy...scanning everything. Again, it feels a little too pedestrian at times, but things pick up once you touch down.
The first setting is an asteroid mining facility, and it's beautiful. Bioware's talent for creating exotic worlds has never been more demonstrable, and soon those old patterns begin again: land on world, ignore fighting, stare in wonder at wondrous horizon, receive hot bullet in back of head. It's always worth it.
Here, an enormous metallic dig site is encapsulated by a shimmering blue bubble shield that, upon impact, flickers with thousands of stray asteroid chunks.
After a familiar fight with Husks, Brutes, Banshees, Harvesters and Ravagers, using familiar tactics and familiar weapons, you'll discover the facility's crew are under mind-control. Leviathan, whatever it is, is trying to cover its tracks. Back to the lab you go.
That's the formula - fight, then root around for a bit. After two more déjà vu-inducing combat scenarios, set against more outstanding vistas, comes the highlight - a trip in a Triton-diving mech 30,000 atmospheres under the churning seas of an all-water planet.
It's virgin territory for the series, a completely uncharted environment at the bottom of some long-forgotten corner of the galaxy, and provides a much needed change - of pace, of scenery, of story. And this is where the saga ends. It would be unfair to reveal more, but questions will be answered. The Leviathan itself weaves into existing fiction effortlessly.
So, is it worth the full ticket price? Not exactly. Two hours of content is a hard sell. The three new environments maintain Mass Effect's peerless visual standards, but the lack of new enemies, attractions or recruitable squad-mates, and the fact you already know the wider ending, makes Leviathan a mystery best left uncovered.
Leviathan begins at pedestrian pace and the combat feels overly familiar, but there's a solid chunk of story here for those who don't mind paying over the odds.