Mass Effect, as its very name implies, doesn’t do anything small. Right from its inception, the bold, original game was to be the first of a planned trilogy when it released in 2007. And though other Xbox franchises have tracked one overarching plot line across three titles — Halo and Gears of War, primarily — those are 10- to 12-hour adventures whose entire tales total around 30 hours. The Mass Effect series serves up that much story in each outing.

The point is, after roughly 100 hours spent with Commander Shepard, you’re invested in him (or her). And it’s multiplied here because of what is perhaps the series’ defining feature: the persistent save file that contains your unique Shepard and all of your choices from the three games — male or female, Paragon (good) or Renegade (evil), straight or gay, celibate or promiscuous, Kaiden or Ashley, who you installed on the Council, and so on.

With the fate of the entire galaxy on the line, the battles get huge.

Yet, despite its long-term vision, Mass Effect has struggled to define itself over the first two entries. Its debut iteration was very much a role-playing game in the spirit of developer BioWare’s previous efforts, featuring an emphasis on dialogue and exploration with players responsible for inventory management. Its combat, while not actually turn-based, could be paused and strategized at any time. The sequel shifted its focus — perhaps inspired by the success of fellow Xbox-exclusive mega-franchise Gears of War — to cover-based, third-person shooting action, excising inventory management altogether and ignoring stoppable combat.

Each design philosophy has its fans — our office remains split, as some of us prefer the original’s RPG leanings while others are proponents of Mass Effect 2’s action-y metamorphosis. Whichever side of the fence you fall on, know that Mass Effect 3 attempts to reconcile both camps, offering two new — well, they’re not exactly difficulty levels — that flank the traditional Role-Playing mode. “Story” minimizes the third-person shooty bits, while “Action” skips out on the conversations. Each is a near-criminal compromise on what is a phenomenal overall achievement, as ME3 manages to present both sides of its gameplay face with pride and polish. More on why momentarily. To finish this point first, though, make no mistake: Mass Effect 3 is very much a sequel to ME2 as opposed to the first game. The inventory remains absent, the galaxy’s planets are still scanned and not landed on/explored with the Mako, and the Citadel — a massive, key hub in the first game that truly felt like a mammoth space base, before being neutered to the point of near-irrelevancy in the sequel — is larger and more of a quest hub than it was in ME2, although it in no way resembles its debut incarnation in either scale or importance.

The new Omni Blade melee attack helps end a lot of close-range battles.

Nevertheless, Mass Effect 3 is, definitively, its own game. And it’s truly an action and role-playing hybrid unlike anything the Xbox has seen. ME3, Borderlands, and Deus Ex: Human Revolution can all be classified as “role-playing shooters,” but each feels very different from the others. For the final entry in the Effect trilogy, combat isn’t simply “acceptable for what’s really an RPG under the hood”; it’s genuinely up to the standards of a premier, dedicated action title. We rolled an Infiltrator (Mass Effect’s sniper class) and paired his long-range weapon with the lethal Scorpion pistol, a sidearm whose rounds stick to their target before detonating a moment later. The resulting firefights never got old: either we exploded Reapers’ heads with the sniper rifle (à la Gears of War) or watched their entire bodies burst like blood-filled balloons before the Scorpion. Played with the right squad members — we preferred Garrus for support, complementing biotic badass Liara, who could use Singularity to float targets in mid-air for us to pick off — Mass Effect 3 makes you truly feel like the galaxy’s preeminent ass-kicker.

This blood-pumping action core kicks off swiftly and never lets up. As the curtain rises on the trilogy’s final act, Shepard is back on Earth, having been removed from active military duty while government officials turn a blind eye to his wild-eyed warnings of the robotic Reaper race that will find humanity and destroy it. Mankind’s home planet is under siege within the first five minutes of the game, of course — faster than the Powers That Be could have ever predicted — and it’s up to your Commander Shepard to hop on the Normandy, get to the Citadel, and beg allies for help as quickly as possible.

Spam your radar while looking for goodies on planets, and you'll draw the Reapers' attention.

Before you know it, you’re neck-deep in quests while feverishly canvassing the entire galaxy, reconnecting with familiar friends and, yes, for you Renegades out there, punching an annoying reporter in the face. Delightfully, everything feels epic and important straight out of the gate: you’re never left wondering when you’re going to get to the meat of the game. There’s no fat to trim from ME3’s 30-or-so hours (we did a pure campaign run — completing every single quest we unlocked — in about 32 hours, later spending more in multiplayer). You’ll net tasks from every direction, including your military superiors, your Normandy-based email account, and even conversations you overhear on the Citadel.

The Reapers don't take kindly to your meddlesome actions.

Unfortunately, the game’s quest log is a broken mess; it’s our chief complaint about an otherwise immaculate piece of software. Many quest items are obtained via a streamlined version of ME2’s planet scanning. This time, you hit LT to ping the area surrounding the Normandy with radar, and when you discover an anomaly, you fly over to the planet, scan it, and obtain the object. No more minerals and no more checking every inch of every world to find the sweetest spots to mine resources. Thank goodness.

It’s still a bit “game-y,” however. Ping too much in a given system and the Reapers will detect you and send ships after you, forcing you to either exit the system and then go right back in to try again, or get run down by the Reaper fleet and be treated to a Game Over screen. It’s nowhere near as tedious as ME2’s scanning, but it’s still the most monotonous part of the game.

Squad A.I. is both smart and capable.