Mass Effect 3 ended the original trilogy in a suitably epic fashion, and the release of Mass Effect Legendary Edition was the perfect reminder of how great a game the third entry is. Challenging without becoming absurdly complicated, the game offers players several Priority missions necessary to complete the main storyline.
Each of these missions is vital, but some, such as Citadel I and III or Perseus Veil, favor dialogue or crucial cut scenes pointing to the next mission. However, others are thrill rides filled with dangerous enemies and nonstop action. None of these missions is a walk in the park, but some are a lot more difficult than others.
Priority: Mars
The first mission is almost always the easiest in any game. Following the short Prologue in which Shepard escapes Earth, Priority: Mars is players' first proper mission in Mass Effect 3. Accompanied by the Virmire survivor and James at first, Shepard soon meets Liara, and the whole thing turns into a Mass Effect 1 reunion.
Mars has some challenging spots, especially the swarm of Cerberus agents near the end, but it's nothing experienced players can't handle. The chase for Dr. Eva Coré is entertaining, but the whole level feels too hand-held, although it's great to see Shepard and Liara in action again.
Priority: Sur'Kesh
Priority: Sur'Kesh takes players to the salarian homeworld of Sur'kesh. The mission involves Shepard rescuing the Krogan female Eve while dealing with an unexpected attack from Cerberus. Like most Priority missions in the game, Sur'Kesh has several waves of Cerberus enemies attacking the player.
The hardest part comes near the end when an Atlas shows up to provide one final obstacle. However, players should have no issue taking it down, considering the area is considerably large with several places to take cover. Shepard encounters Mordin during this mission (provided the salarian scientist survived Mass Effect 2), and that alone makes it incredible, if not necessarily difficult.
Priority: Tuchanka
Mordin and Wrex, two of the best companions in video game history, play a crucial role during Priority: Tuchanka. Shepard and his team take Eve to the krogan homeworld to cure the genophage once and for all. To reach the Shroud tower and spread the cure, Shepard must deal with countless enemies, including brutes, marauders, and husks.
The battle's climax involves a race against time to summon Kalros, a massive thresher maw capable of taking down the Reaper protecting the Shroud. It's an intense moment, but Shepard can ignore the multitude of enemies and focus on activating the hammers. Priority: Tuchanka is a turning point in the game, a promise that things will only get more challenging in the next missions.
Priority: Palaven
Despite being the second main mission, Priority: Palaven can be surprisingly challenging. Shepard travels to Menae, Palaven's moon, to secure the help of the turian primarch. The Commander must first help the turians turn the tide against the wave of reapers trying to conquer the moon.
Priority: Palaven features the first encounter with brutes, and some players might have difficulty with the last leg in the mission, which involves a coordinated attack by two brutes and countless marauders. However, Garrus, arguably the best companion in Mass Effect, is there to help, making things better.
Priority: Citadel II
The Citadel plays a crucial role in the Mass Effect trilogy. The third entry showcases it constantly and nearly destroys it during the mission Priority: Citadel II. The plot involves a coup attempt by Councilor Udina and features Shepard's first encounter with the loathsome Kai Leng.
Unlike other Priority missions in the Citadel, Citadel II is no conversation and all action. Shepard and his team kill Cerberus agents left and right on their way to rescue the Council and deal with Udina. The mission always results in Thane being critically injured (as long as he's there in the first place), but the Virmire survivor can also die if Shepard doesn't earn their trust back. The mission is critical for Shepard's crew, adding an extra layer of difficulty.
Priority: Cerberus Headquarters
Players will spend the game's duration chasing down Cerberus and attempting to take them down. By the time Shepard reaches the organization's headquarters, the Commander is more than ready to deal with whatever Cerberus throws their way.
Kai Leng is the mission's most challenging threat, but he's surprisingly easy to defeat compared to Shepard's initial fight with him in Thessia. Indeed, Kai Leng is a great villain, but his boss battle is underwhelming, making Priority: Cerberus Headquarters feel surprisingly anti-climactic.
Priority: Horizon
Before Shepard storms Cerberus' Headquarters, the Commander first raids the Sanctuary facility, a supposed haven from the war that's actually a Cerberus experimenting facility. The mission decides Miranda Lawson's fate (provided she survived the suicide mission), and if players don't play their cards right, they'll end up with another dead squadmate.
Priority: Horizon has the usual enemies but in considerable amounts. The final battle puts Shepard against banshees and brutes, which coupled with the fortified ravagers encountered in the previous confrontation, make for a particularly challenging fight.
Priority: Thessia
Priority: Thessia takes players to the asari homeworld to find an ancient prothean artifact that may hold the key to finding the Catalyst. Thessia lies in ruin, much like Earth during the game's prologue, but Shepard and their team should have no trouble getting to the artifact.
What makes the mission such a challenge is the battle against Kai Leng. The Cerberus agent has several tricks up his sleeve, and some players might have trouble dealing with him. What's worse is that the battle is merely a distraction. Shepard will never win, and Kai Leng will always get to the artifact first. Priority: Thessia is the one mission Shepard fails, a heavy blow to players' morality.
Priority: Geth Dreadnought/Rannoch
Tali is not only one of Shepard's best romances in Mass Effect but also a compelling and intriguing companion and friend. She reappears in Mass Effect 3 during the Rannoch missions, which involve infiltrating the geth dreadnought to deactivate the reaper signal controlling them. Shepard must then lead an attack force to infiltrate the reaper base in Rannoch to destroy it.
The geth dreadnought has a particularly challenging portion where Shepard must fight enemies while avoiding a deadly laser. Rannoch has a cascade of hostiles plus the added threat of a reaper lurking in the distance. In the end, the Commander must single-handedly face and defeat said Reaper with a prototype laser and some help from the Normandy. These two missions are a highlight in Mass Effect 3, offering incredible cinematic sequences and grueling challenges that will prove if players are truly ready to face the reapers.
Priority: Earth
Mass Effect 3's final mission takes Shepard back to where it all began: Earth. The Commander shares numerous goodbyes with his crew, past and present, before heading to fight the reapers. The mission is basically a parade of enemies that come to kill Shepard and will stop at nothing to achieve it. The last fight, in particular, is an absurd overflow of hostiles: banshees, brutes, marauders, and reavers will all come at once, forcing players to distribute the squad intelligently.
The last leg of the mission, which involves boarding the reaper ship, can end with the death of Shepard's two companions if players don't get sufficient EMS throughout the game. The ending, of course, is a lengthy conversation that determines how the reaper threat ends, but everything leading up to it is non-stop action and danger lurking in every corner.