Leviathan, BioWare‘s first paid-for single player DLC for Mass Effect 3 (the studio has previously released the Extended Cut for free, as well as the paid-for Firefight weapons pack), is – by itself – an enjoyable enough expansion.
It starts off with you going to the Citadel lab of a certain Dr. Bryson to investigate his research into potential war assets to use against the Reapers. This is, in many respects, Leviathan’s greatest failing; if you’ve finished Mass Effect 3 there’s little incentive to play Leviathan.
Sure you learn more about the Reapers – and the race that created them – and also gain additional war assets and new dialogue options with the Catalyst, but ultimately, no matter how you choose to play Leviathan, there is no real impact to the main game itself.
This DLC would have been far more beneficial, or rather, players would have gained far more from it, if it had been included in the game to begin with. If, on the other hand, you have not yet finished Mass Effect 3, then this is clearly not a problem.
Not long after meeting Dr. Bryson, he is, shall we say, “taken out of the equation”. It then falls to Shepard to track down his daughter, Dr. Ann Bryson, who is currently investigating a potential Reaper-killer, the Leviathan. At one point Shepard exclaims that, “Leviathans are vital to the war effort!”
Obviously they aren’t – if they were they would have been included in the main game to begin with; they are a war asset, nothing more, and hardly essential. Which is another aspect of the DLC; Leviathan is a good two to three hour expansion but it never feels essential to your experience of the game. As a comparison, Leviathan is akin to Mass Effect 2′s Overlord more so than Lair of the Shadow Broker, which is to say you can play the game and get the most from it without touching Leviathan.
Even so, there are moments of charm and neat little nods to fan service; EDI refers to Galaxy of Fantasy, an invented RPG, and discusses a weapon player forums describe as “overpowered”. She also bitingly dismisses Shepard’s jest about the Loch Ness monster at one point, and while the Loch Ness monster may not be real, the Leviathans are and they do indeed dwell beneath the waves.
Naturally, it’s not easy to find them, however. Leviathan can descend to a pedestrian pace at times, quite literally, as you guide Shepard around Dr. Bryson’s office on three occasions looking for clues to advance to the next stage. Leviathan takes you to a mining asteroid, a base on the edge of a cliff crumbling under a Reaper attack, and, finally, to the depth’s of the ocean floor to confront the 
Leviathans in person.
As DLC, Leviathan can perhaps best be described as competent. Too short for the entry fee of $10/€10 or 800 Microsoft or BioWare points and ultimately, having no real bearing on the outcome of Mass Effect 3, Leviathan may be best passed by in favor of future content. Alternatively, if you are keen to learn more about Shepard’s greatest foes and the species responsible for their origin, or have not yet completed the game, then Leviathan is something you should consider.
Leviathan is not the worst downloadable content BioWare has released for the Mass Effect series, nor does it ever quite manage to feel like a completely necessary addition to the game.
Rating: 
This review is based on a retail copy of the Xbox 360 version of Mass Effect 3: Leviathan by BioWare distributed by Electronic Arts.
