Warning: Spoilers, obviously.
The Mass Effect Trilogy has many outstanding moments, but one stands head and shoulders above them all: The Suicide Mission. Much as everyone argues over Mass Effect 2's relative merits, I think almost everyone can agree that, final boss notwithstanding, its grand finale is amazing.
In many respects, it is a master class in how to bring a massive game to a satisfying conclusion. The entire game is spent building to the moment that you take the plunge and bring the fight to The Collectors—a powerful race with mysterious motives. Where most triple-A games run out of gas by their midpoints, Mass Effect 2's story reaches a crescendo when you dive through the Omega 4 Relay for the final mission.
Its stakes are the secret to its success. When you embark on the Suicide Mission, it's with the knowledge that literally anyone, even Shepard, can die. Its a potent source of tension that is absent in nearly every other game—the sort that drives successful shows like Game of Thrones. If you have the nerve to play without a guide, it's a white-knuckle experience until the moment that Shepard safely jumps back aboard the Normandy.
BioWare are aware of this tension and take steps early on to begin building it up. The Omega 4 Relay becomes accessible once you obtain the Reaper IFF, but you don't have to enter it right away. Instead, you are encouraged to gather materials to upgrade your ship, find the best weapons, and complete loyalty missions before diving in. It's reminiscent of Chrono Trigger in the way that you can take on the final battle pretty much whenever you want, but with dire consequences if you decide to head in too early.
Highlighting the Omega 4 Relay early has the effect of heightening its sense of danger. It encourages you to wonder what you will find on the other side, and whether you are prepared to take it on. When you finally decide to dive in, it's with some trepidation. Have you done everything you need to prepare? Are you ready to end the game? Mass Effect 2 puts the power to pull the trigger on the ending in your hands, but asks, "Are you absolutely sure?"
Just to give you an extra push, The Collectors kidnap several of your crewmembers and spirit them away through the Omega 4 Relay, including Kelly Chambers—the charming yeoman you can get to feed your fish. You can go after them immediately or choose to wait and prepare, the implicit understanding being that choosing to wait will result in them suffering a horrible death. Whether you're ready or not, it's pretty much go time.
When you opt to enter the relay, you are reminded that the Normandy may not survive, and that includes your squad members. More than likely, you will find yourself attached to at least a few of them, and you won't want to lose them. I was sweating bullets at the prospect of sending Tali, Mordin, Jack, Garrus, and Legion to their deaths.
But in the end, there's nothing for it. You take a deep breath, close your eyes, and hit confirm. And it's on to Mass Effect 2's amazing finale.
The Suicide Mission
The finale begins, jarringly enough, with sex. When you trigger the Suicide Mission, the crew member you've been hitting on through the game will approach for a quick roll in the sheets. It doesn't play well here owing to the urgency of the situation—your subordinates are literally about to be liquified—but it's a BioWare tradition for the obligatory sex scene to take place on the eve of the big battle. With that out of the way, it's off to Collector space.
When you enter the relay, the first thing you see is the familiar blue hyperspace tunnel—a moment for you to catch your breath and reflect on what you're about to see. Then you're suddenly in the middle of a massive debris field: remnants of other ships that have tried and failed to pierce the veil. The Collector defenses come alive and begin hammering the Normandy as it twists through the debris field, testing its new plate armor as you go. Even with the Normandy's fancy new defenses, which you painstakingly build up by mining a multitude of planets over the course of the game, the enemy still manages to breach the cargo hold, forcing you into a quick firefight. If you don't upgrade your ship, say adios to a couple of your squad members (Tali will get straight-up vaporized, which is terrifying).
After a brief but wild ride that sees you take some revenge on the Collector ship responsible for destroying the original Normandy, you crash into the enemy station and prepare to move out to the goosebump-raising tune of the main theme. Mass Effect's music, I should mention, is never better than it is here. It accentuates the fear and mystery of entering Collector space with a low, rumbling synth, then slowly builds as you plunge further and further into the heart of their space. Mass Effect's soundtrack is great in general, but in my opinion, they really nail the music for the Suicide Mission.
Before heading out, you gather your team and make your first choice: how do you get into the central chamber? You are confronted with a number of options, the best of which is choosing a ventilation shaft through which to send a team member. Miranda heavily suggests a tech specialist, which makes the decision easy enough, but there are still some nerves involved. What if Tali or Legion don't make it? The next choice is harder: Who will lead the second team? You are told to pick someone who will command "loyalty through experience," making the choice a bit less cut-and-dried.
After making your choices, the descent begins into the heart of the Collector base with the team that you've painstakingly assembled over the course of the game. The Collector base is an eerie series of winding tunnels filled with organic technology, drones and other, more powerful, enemies lurking throughout. As you fight, your chosen specialist will announce that the path is blocked, and you will have to hurry to open a series of valves so they can proceed while the legend "Specialist in Danger" flashes on the screen. Meanwhile, the alternate squad will send periodic updates, heightening the sense of urgency as you press through the base. If you haven't taken the time to build up your characters, you may find yourself bogged down in firefights, and that's when things get really hairy.
Once you're finally through, you find your crewmembers, but it's an open question of whether you were fast enough. You see a Horizon colonist melted into black sludge in a horrible sequence; but if you opted to leave in time, the rest of the crewmembers will be safe (if not... well...). It's here that you learn still a bit more about the Collectors, as well as make your next important choice: a Biotics specialist who can hold off seeker swarms while you advance. The sequence that follows is another firefight as you hide within your chosen specialist's bubble and work your way forward.
At last, the truth becomes clear: The Collectors are using the organic material from the humans they capture to build a Reaper. A Human Reaper. It's a little silly in hindsight, but that doesn't make your first sight of its massive, Terminator-like skeleton any less effective. Knowing how dangerous a single Reaper can be, the stakes rise that much further.
Alas, the battle that follows is one of the weakest in the series, as you go full Contra on the Reaper and shoot out its weak points. It's not very satisfying, but if you think of the entire mission as one big final boss fight, it gets a bit better. When it's gone, you are confronted with a seemingly important choice: Blow up the Collector base or risk leaving it with Cerberus? It seems like an easy decision given Cerberus' sketchiness, but in the heat of the moment, without Mass Effect 3 to guide you, it can be a tough choice. I ultimately opted to blow it sky high, as I imagine most people did.
The final scene finds Shepard and company sprinting across the exploding base to leap back to the Normandy. And this is what I love: Shepard can actually fall to his death! Even better, if he falls to his death, the game isn't over! Instead, Joker addresses the Illusive Man and Shepard's story is finished. If you want to play Mass Effect 3, you'll have to roll a new character (imagine if you could play in a world with a dead Shepard?) It's a really remarkable ending; something I can't remember seeing in any other game. And that goes for the rest of the mission.
The Suicide Mission ultimately works because it has something that other games of its ilk lacks: actual stakes. Triple-A setpieces are a dime a dozen these days, but they rarely hit as they're supposed to because there's no actual sense of danger. You know that if you screw up and die, you can just revive and try again. It makes the experience rote and frankly boring. But in Mass Effect 2, you know that if you lose a squad member, they're gone. And when you load into Mass Effect 3, they'll still be gone.
To be sure, the danger in Mass Effect 2 isn't as high as it could be. BioWare telegraphs pretty heavily what you need to survive your trip through the Omega 4 Relay, and the final battle makes what should be optional Loyalty Missions pretty much mandatory. If you're paying attention, you should be able to make it through the Suicide Mission on your first try without losing anyone.
Nevertheless, the Suicide Mission continues to stand out in my mind as one of my most memorable gaming moments. I played the original Mass Effect, but it was in Mass Effect 2 that I really bonded to my Shepard and her motley crew. Playing without a guide or any real knowledge of what was to come, the final mission was a harrowing ride as I made snap decisions on the fly and just prayed that nothing would go wrong. In the end, I got everyone out alive, but I knew plenty of people who didn't (and then reloaded and did it again, but if you're willing to accept the consequences of your actions...) If you're reading this, you've almost certainly already finished the mission yourself. But for your sake, I hope you managed to avoid spoilers, because it's so much better without them.
With that, I would suggest that Mass Effect 2 is the closest the series has come to putting forth a scenario where all of your decisions actually matter. Once you're through the Omega 4 Relay, Mass Effect 2 presses down on the accelerator and doesn't let up, delivering on the promise of the battle that it hypes throughout most of its story. It's a great example of build-up in a game, allowing you to recruit and get to know your team at your leisure, then putting their fate in your hands.
I feel like people will argue until the end of time about whether or not Mass Effect 2 is a good game; but for me at least, it's my favorite game in the series, and the Suicide Mission is a big reason why.