Here's the problem. Leviathan is easily one of the best bits of DLC that Bioware has ever put out - at least matching the quality of Lair of the Shadow Broker, and arguably surpassing it in many ways. It shakes up Mass Effect 3's style, tries a few new things, offers a couple of cool new locations, and is far more than simply a new mission to throw onto the pile. Unfortunately, it's about the Reapers... and while digging into their backstory might have been cool once, that ship has long since sailed. Right into an iceberg.​

The latest DLC, a two-hour sightsee spanning three new environments and a research lab on the Citadel, where Shepard turns detective in search of towering Reaper-killing organisms called Leviathans, exists in a world where the war hasn't yet been won or lost. It's entirely incongruous. You already know the plot, and therefore anything threatening to upset it rings hollow and lacks risk.

"Leviathans are vital to the war effort!", remarks Sheppard. Well, no. You already won. There's an air of inconsequentiality to the whole thing, a bit like Titanic in space.​

In short, Leviathan's gameplay reminds you why the series is so good and of the potential it still has. The adventure spans three major missions, each interspersed with visits to a new area of the Citadel. And it's here, in a mysterious clue-filled lab, that BioWare is able to really have some fun.

Within minutes, the traditional pattern of "meet quest giver, run off to mission" is abruptly altered. Shepard is wrapped up in a detective operation, scouring the environment L.A. Noire-style for pointers as to what to do next. There are fan-pleasing references and nods to old Mass Effect plots aplenty, as well as lots of time spent with EDI, one of the surprise highlights of Mass Effect 3.

[...] The locations are also real stars of this add-on, however briefly they are visited. Corridor sequences are wisely kept to a minimum as the game's trio of planetary excursions take you on a whistle-stop tour around the Galaxy Map. There's a Dead Space-style creepy mining colony with a chilling atmosphere and some truly unnerving moments. Then there's a precarious, rusted settlement left clinging to a giant cliff face, mid-Reaper attack. And there's a gorgeous ocean world, whose undulating waters rock the creaking floor beneath you.

Gameplay innovations are not limited to the CSI-style investigations in the Citadel lab. Leviathan takes players underwater for the first time in a brief section of aquatic exploration whose looks are reminiscent of BioShock 2's sojourns outside Rapture. Less impressive are the combat objectives borrowed from Mass Effect 3's recent multiplayer expansions. One section sees Shepard having to escort a drone around the battlefield (introduced in the Earth multiplayer DLC). Another sees you lugging packages from one area to another (introduced in Rebellion and referred to by players as the "pizza delivery" round).​

Maybe some day we could play a Mass Effect that focuses on the discovery of beautiful new worlds. Leviathan brings players to two of the best-rendered worlds seen in the series. Mass Effect hasn't looked this good since the visually magnificent Mass Effect 2 expansion Lair of the Shadow Broker. Too bad that the tours of these new places are so brief.

Perhaps in the future we could play a Mass Effect horror game, which Leviathan almost turns into, during a creepy sequence set in the second-weirdest space-mining facility ever seen in an EA-published game.

[...] Leviathan nevertheless conveys the sensation that Shepard's time is up. Her adventure had its grand finale in Mass Effect 3, which leaves this mid-mission expansion feeling like watching a very long deleted scene. There are no great secrets to be learned about Shepard.​