An epic finish to what is possibly gaming's most important Sci-Fi trilogy.
Starting off with Shepard undergoing a court martial for either the destruction of a Batarian colony or cooperating with Cerberus (depending on whether or not you played the Arrival DLC for Mass Effect 2), Earth comes immediately under attack by the Reapers. After a quick tutorial and intro sequence, Shepard is back in action trying to rally the various sentient species in fighting the Reapers and taking back Earth, as well as attempting to defeat them using a mysterious artifact known as "The Catalyst".
Mass Effect 3 takes great strides in having your decisions add up, with the use of "Effective Military Strength" tallying up your accomplishments, towards a final score that will determine how will the final battle against the Reapers will go. Other times, those decisions are shown through more direct manners, like a chance meeting, a rekindled romance or an email thanking you for an old deed. Many of these encounters can directly affect the story path, which gives this great sense of ownership over the experience and can shape the tale in a vastly different manner throughout the game. The game does a really fantastic job of having your previous decisions matter, with various side missions and important changes resulting from many of your past decisions and encounters.
The gameplay doesn't feel like a major change from Mass Effect 2, but it offers enough small changes to improve this iteration. Planet exploration is still completely gone (as it was in Mass Effect 2, save for the Overlord DLC), but in place of the dull scanning mechanic in Mass Effect 2 you now have a more interesting mixed exploration focus, where players can go into Reaper space to look for war assets and items. The risk/reward element allows this mechanic to be more exciting, even though it mainly combines the space travel and scanning into one mechanic. The game also removed the various minigames for hacking, with data and money now a click or button press away (with all safes inconspicuously unlocked).
The combat has also undergone a change, with players of all classes now capable of wielding all weapons, only limited by the weight which affects power cooldowns, making players have to choose whether to rely more on weaponry or biotic and tech abilities. Allies are now smarter and more capable with their abilities and are more customizable with weaponry and abilities. Enemies now have many variants to keep players scrambling such as a shield wielding Cerberus or a rocket launcher wielding Geth enemy, with the three main enemy factions (Geth, Cerberus and Reaper) all having different tactics and changing up the combat. The levels themselves still suffer from an unnatural feel when in combat with easy to spot cover points in an area making upcoming combat obvious, but with the threat of invasion everywhere at once and the changing Galaxy as a result, it makes more sense here at least than in previous titles.
It's not a perfect game, and with two amazing predecessors behind it Mass Effect 3 had a lot to live up to. The game still has the player spending too much time in the Citadel looking for side quests and often slows the pace of the story as a result, with some side missions feeling out of place here given the scale of the conflict at hand (fetch quests from artifact hunters should be far from Shepard's concern). The Effective Military Strength you have is a nice way to measure your decisions and choices towards the end goal, but it feels impersonal and relies too much on multiplayer* (which is what Mass Effect fans feared when multiplayer was announced). The combat still feels a bit stiff and awkward, with level design and options not opening themselves up to many different ways through a situation, which was a complaint held for Mass Effect 2. Even though the series tries to stay welcome to newcomers, Mass Effect 3 feels like the last 300 pages of a 1000 page book.
Despite Bioware's best efforts, it doesn't lend itself as well to series newcomers as Mass Effect 2 does due to the culmination of decisions and bevy of characters and factions to know here, so I urge anyone who wants to get into the series to try it from the start if they can, or if they happen to be a PS3 owner to at least start from Mass Effect 2 (which offers an interactive comic on that version). The karma system is also a bit out of place in some situations, while the game does offer some tough choices the binary decision making can dilute the importance of some decisions when you are thinking more about your paragon/renegade scale over which decision you would really want to make. The ending is one part of the game I won't go into detail here due to the risk for spoilers, but I will say that it can be very polarizing, being a bit abrupt with just a few plot holes behind it, but it was far from terrible and definitely made good use of the EMS you earned and decisions you made*.
Overall, Mass Effect 3 is a well-made and satisfying resolution to the series that makes good on the promise of letting us carry over our decisions from the first game, while giving fans more choices to make here for the final confrontation. The story is well written, the gameplay is solid, the combat and RPG mechanics combine and add to the best improvements from the last two games, and new addictive multiplayer mode add up to make this a great final mission for players to undertake as their Commander Shepard. Regardless of what you make of the ending, I guarantee you will have full ownership of the story. Discussing my experiences and decisions with other fans really shows just how ownership I had over my experience and makes this a series unlike any other.
*As of the free Extended Cut DLC, the EMS necessary for the best ending has been lowered drastically allowing players the chance to get the best result without having to touch multiplayer, while still rewarding those that do.
*The Extended Cut DLC has cleared up the ending while giving us a more proper send off to the characters and races we know from the series, with a detailed epilogue explaining the fate of the galaxy.