Here's some spoiler free copy paste from a review:
(We'll keep the spoilers to a minimum in this report, both for Mass Effect 3 in general and the "Citadel" DLC specifically, but the YouTube videos I link to do contain complete scenes from the DLC. Expect spoilers if you click through.)
Mass Effect 3 has had several downloadable content packages released which expand on some aspects of the single-player game, including most recently the "Omega" package, but this week Bioware let loose rather a different single-player pack: the "Citadel" DLC. What makes it different isn't just that it includes participation from every major Mass Effect crew character and voice actor—though that's a welcome change from some past Mass Effect DLC packs—but that the focus of the package isn't really on tossing Shepard and crew into another combat arena. Instead, the DLC quite literally lets the crew of the Normandy get boozed up and partied out...and it's great.
The first game in the Mass Effect series was very much a formulaic, cookie-cutter Bioware game, complete with the requisite Tower of Hanoi puzzle. But over the series' three games I've come to care deeply about Shepard and the crew of the Normandy. The friendships and romances formed are a significant part of the attraction, far more so than the combat, which has never really been my favorite. The role-playing aspect has been the reason I've stuck with Shepard and company. The moments in Mass Effect 3 that were the most powerful and beautiful weren't the huge set-piece explosion-fests, but the bits of character interaction between missions—the kind of things that people often write fan fiction about. What do the characters do when they're off-duty?
The "Citadel" DLC contains an interesting mission as its base, but its true purpose is to provide Commander Shepard and the Normandy crew with a giant apartment on the Citadel in which to throw the mother of all parties (I am not being metaphorical here). The DLC is a big, wet, sloppy three-hour fan-service kiss... and as everyone's favorite Turian once said, "I'm OK with that."
The DLC's tone is light throughout, and every single main crew member from all three Mass Effect games gets at least a few minutes in the spotlight. Even the main plot mission is carried off with tongue firmly in cheek. Characters offer up quips more often here and every scene feels like it's done with a nod and a wink to the fans.
It may be too silly for some fans, however. Mass Effect 3 is generally a pretty serious game, dealing with a galactic-level extinction event and the destruction of all known life. Shepard's team is on the clock for the whole game, trying to rally support for their war against world-destroying enemies, and the player is constantly reminded that even as the crew is relatively safe flying around in space, Earth is under siege. The rare bits of relaxation in the game feel like genuinely stolen moments, and there's always a bit of guilt that you're not trying harder to save Earth.
"Citadel" upends that. Shepard and the crew are on shore leave—dropping the Normandy off at dock and gettin' crunk in Admiral Anderson's enormous Citadel apartment. Without dropping spoilers, the DLC is timed to take place after the midpoint in the game. If it were inserted at that point into my first playthrough of Mass Effect 3, the interlude would seem ridiculous and out-of-place, releasing the game's tension like a balloon rapidly deflating. "Sure, the galaxy is at stake," it seems to say, "but let's all party and ham it up for the camera for a bit!"
But for most of the players interested in this particular DLC, it's not really taking place midgame. For those who have played through the game already, the DLC functions as Bioware clearly meant it to function: it's one last big, beautiful goodbye.
Every important crewmember from each game gets a moment alone with Shepard. Some scenes are heartbreaking; others will make you smile so hard that your face will be in danger of cracking. Even love interests given short shrift in Mass Effect 3 (like Miranda Lawson and Jacob Taylor) are allowed one last extended scene with Shepard.
"Citadel" is just that—a series of "one last times," stuffed full of treasure for those who love the series and its characters. The folks at Bioware have absolutely outdone themselves, cramming in an almost overwhelming number of inside jokes and giggles. The DLC even offers a direct response to one of the most infamous bits of Mass Effect fan-generated insanity to ever pop up on the Internet: a creepy-weird bit of armchair chemistry theorizing about what ship engineer Tali's sweat would smell like.
For players like me who are emotionally invested in the series, "Citadel" is excellent. It's like a gift from Bioware, a perfect bit of fanwankery made canonical. Whether or not it fits in with the larger tone of Mass Effect 3 is questionable, but it gives us all one last chance to see Shepard and his crew happy. This can sometimes be a bit too much, like eating your entire haul after trick-or-treating, but who doesn't want to overdose on candy every once in a while?