Quality Over Quantity: In Mass Effect Saren tries to cure the krogan genophage so he'll have a krogan horde at his back. In Mass Effect 2 krogan warlord Okeer derides the idea of sheer numbers, calling it the mistake of an outsider. He himself has created Grunt, whom he considers a perfect krogan warrior.
Okeer: The galaxy still bears the scars of the horde. But it will learn to fear the lance.
288 years before the main events, the quarian race lost their home planet to the geth, forcing the survivors of the war to flee. At the heart of their culture is a strong sense of loyalty and a deep attachment to their home world, beliefs passed down by their ancestors. For this reason, almost every quarian you encounter is devoted to finding a way to take back their home world from the geth, despite the fact that no current living quarian has ever stepped foot on the home world. However, according to Tali in ME2, it would take 60 years for them just to acclimate to Rannoch, and ten times that for any other planet.
In 3, the loss of Khar'shan turns the batarians into remnants. You can coerce them into rallying around what's left of the Hegemony's navy, providing a boost to your War Assets.
Prothean technology is remarkably durable, most of it still working fifty thousand years later. Granted, though, there is a fair amount of it that's gone offline, and what's left tends to be glitchy or breaking down. The mass relays were designed to go at least fifty thousand years without maintenance, though. Not that they're Prothean, anyway...
Krogan architecture was designed with this in mind, with Tuchanka having already suffered one world-wide nuclear apocalypse. Krogan hospitals are actually built more like bunkers because critically injured krogan in the midst of blood rage tend to attack anything.
Played absolutely straight in the first game, where your squad can be comprised of: Alliance officer, marine, former security officer, mercenary, wayward teenager, and archaeologist.
Taken Up to Eleven in the second. Squadmates include: two Cerberus operatives, former STG agent, escaped Cerberus test subject, tank-bred krogan, vigilante, asari Knight Errant, ruthless assassin, geth expert, geth, veteran mercenary, master thief.
Mostly averted in 3, as your original misfits have all become movers and shakers of galactic importance (Reaper task force leader, progressive reformist leader of a near-terminal Proud Warrior Race, quarian Admiral, second human Spectre, and Shadow Broker). Your new teammates are a professional human Badass, an embodied AI, and the last Prothean, who was basically the Renegade Shepard of his time. Yeah.
Railing Kill: Possible with biotic powers or with weapons that can cause knockback like shotguns.
The Mass Effect 3 multiplayer mode used to suffer from major abuse of this. It has since been changed, with knocked-off Cerberus troops using their boot rockets, normally used to slow descent when falling, to boost back up.
Ramming Always Works: Played straight in the first game: Sovereign makes a direct run at the Citadel and plows through anything in its way. Subverted in the third game: when it becomes clear that the Reapers can't be defeated conventionally, a Codex entry notes that kamikaze attacks could be an effective alternative... except the FTL system used by every Council species (including humans) has a built-in safety feature that prevents high-speed collisions. Given that FTL technology was devised by the Reapers, this "flaw" is likely intentional.
Rape, Pillage, and Burn: What happens to a number of colonies throughout the games. Including Shepard's hometown, if you went that route.
Ray Gun Gothic: It's subtle, and certainly a more modern take than is usually traditional, but the game is as much a tribute to the aesthetics of early Space Opera as it is to the plots. Almost every ship is shiny like new, and even the clothing captures the same 'space age' feel of '70s/'80s-style sci-fi without being too corny.
Real Is Brown: Mass Effect 1 seems to have places where this trope is averted and played straight in equal amounts, the most notable aversions being the Citadel and Virmire. In 2, however, the aversions are much fewer in number, and even tropical locations tend to be painted in brownish shades, and, judging by the demo, 3 seems to follow 2's example. Justified in many cases: Tuchanka, krogan homeworld and major location in both 2 and 3, is a Death World that has been rendered further uninhabitable by nuclear war. Many other locations take place on atmosphere-less cold rocks with enclosures fit for habitation. And in 3, the Reapers destroying everything equals lots of dust.
The asari and krogan often have lifespans over 1000 years.
In the case of your squadmates, Liara states she's 106 and barely considered more than a child.
While we don't know how long the Krogan Rebellions lasted, Wrex hints that he fought in them during his youth. When one considers they started in 700 AD, this puts Wrex's possible age at nearly 1500.
Which says something when you realise that Warlord Okeer was stated to be even older, with the implication that as a veteran of the Krogan Rebellions, he was roughly the same age as Wrex's father.
Krogan may actually be immortal as far as natural causes are concerned; ironically, their deadly homeworld fauna and violent way of life result in the average krogan living a shorter life than a human. Exceptional individuals like Wrex, however, end up notoriously hard to kill due to millennia of accumulated combat experience.
And then there's Javik in Mass Effect 3. Although it's not exactly said what age he really is minus the 50,000 years in stasis; though he says that by the time he was born, the Reapers were already well into eradicating his race.
Real Time with Pause: Practically essential. It lets you figure out where the enemy is, not to mention distribute orders to your squad members. For what should be obvious reasons, Mass Effect 3's multiplayer mode disables pausing, making adjusting to multiplayer in the third game more of a challenge than usual.
Recurring Riff: Possibly the most prominent appearance of the Mass Effect theme is during the unveiling of the Normandy SR-2 early in the second game.
Recursive Precursors: The Mass Effect universe is the Trope Codifier for this trope; there is an extremely long line of civilizations that came before our own, starting with the Protheans 50,000 prior to the games, and ending with the Reapers at least ten billion years ago.
Red Oni, Blue Oni: Series-wide, Blue has represented Charm/Paragon and Red has represented Intimidate/Renegade.
Religion of Evil: The geth's worship of the Reapers basically boils down to this; after all, how benevolent can a religion be when one of its core tenets is 'exterminate all organic life'? Only the 'heretic' geth follow that particular path, though; the other 95% of the geth practice more benevolent, or at least less destructive religions.
Replacement Mooks: Reapers are fond of this trope. Their first Slave Mooks were the rachni, who were hunted to near-extinction. Their second were the geth heretics, who were utterly crushed in the first game. In Mass Effect 2, the Collectors have their shot, and are promptly discarded when they lose. Wonder who's next to check out their Wanted Ads?. Indoctrinated humans, batarians, turians, asari, krogan...
Restricted Expanded Universe: Bioware has stated that the official continuity is what happens for the player. Because of this, the novels and comics have to avoid mentioning any of the decisions players can make in the games. The exceptions are thus, appropriately vague: The second and third novels reference the Council, but do not specify if it is the original, human-led, or human-only.Retribution and Inquisition state that Anderson leaves the Citadel in disgust at the Council's refusal to acknowledge the Reapers, but do not specify whether he's the Councilor or Udina's aide.
Word of God has since said that Udina is the Councilor and Anderson was his aide, he is even stated to be an admiral in Retribution, this has more to do with plot reasons for future novels and games however.
Some would argue the new "it's-not-ammo" ammo system in the second game counts. It's handwaved as a new universal "upgrade", but mentions of heat sinks in periods well before that are made too.
The Extended Cut DLC added some major ones to the original ending of the third game, notably that the mass relays are no longer destroyed, simply damaged, with the Catalyst's mention of it even getting cut, and the Normandy is shown leaving the jungle planet after minor repairs, instead of being stranded, if EMS is high enough.
A subtle one can also be seen in the quarians: in Mass Effect 1, their weak immune systems are stated to be from living on sterile ships, and it is implied that the quarians don't need to wear their suits on the fleet (Tali's mother died of a shipwide airborne infection). In Mass Effect 2, quarians are shown on the fleet wearing suits, and in Mass Effect 3 being "trapped" in the suit is an important part of Tali's character arc.
Retraux: The games come replete with a faux film grain filter to complete the seventies and eighties throwback feel.
Retro Universe: The entire ME universe is built from tropes present in the seventies, with some from the eighties thrown in. Even the art styles are reminiscent of that era. Most people don't even notice, though, until it's pointed out to them.
Revolvers Are Just Better: From the third game: the M-358 Talon pistol... with added awesome for being a revolver-shotgun hybrid. No seriously, it shoots multiple projectiles, has the highest base damage of all pistols and higher than some actual shotguns and requires six revolving blocks of ammo to offset the ridiculous heat it generates. Yeah...
Ridiculously Human Robots: The geth, from having a blood-like fluid spatter when they're wounded, to doing some serious soul-searching constantly to the point of adopting religions, to screaming in pain when they die. Also, Legion gestures when talking to Shepard.
Can be taken Up to Eleven in the third game, depending on player choices.
Ring Menu: A lot of them are already in the PC version, from the main menu to the dialogue system. Even more so on consoles, where pretty much everything (weapon selection, power choice, ...) gets ringmenued.
Rite of Passage: Several species have them in the games. Constantly mentioned is the quarians' Pilgrimage: when a quarian reaches adult age, they leave the Flotilla and go out into the galaxy, not allowed to return until they have found some kind of gift, some item, resource, or information that will help the Flotilla. Then there's the krogan rite of passage, which, true to their origin and general nature, involves killing lots and lots of things. Followed by five minutes of frantic running from a Sand Worm.
Or killing said sandworm, if your name is Urdnot Wrex, or Commander Shepard and serving as part of a krantt.
Or, in the case of shamans, spending seven days trapped in a cave with barely enough food to last.
The turians also have a rite of passage, one which is a little more mundane - conscription and military service from age 15, for another 15 years.
Garrus: Adolescence? Can't we just take him to Omega, buy him a few lap dances?
Robot Religion: The heretic geth form a religion based around worship of the Reapers and the extermination of all ascendant organic life in the galaxy. The rest of the geth, that is to say, most of them, practice a more benign religion that involves every race determining their own destiny.
Also subverted. The Reapers are insulted by the geth worship. Which may make lot more sense given The Reveal at the end of Mass Effect 3.
Robot War: A few. First there was the war between the geth and the quarians, which turned out to be a mistake; the geth really want to live in peace, and the whole thing never would have happened if the quarians hadn't shot first, which ended badly for the quarians. Then there was the more recent invasion by the heretic geth, led by Saren, which ended less badly for the galaxy. And then there's the ongoing war against the Reapers, which hasn't ended well for any organic civilization in the last forty million years.
Apparently the cycle of synthetics turning against organics has gone on for so long that someone came up with the Reapers as a solution to the problem. A synthetic entity no less.
Roma: The quarians are an odd mix of Roma and Space Jews; their lifestyles are reminiscent of Roma, but their beliefs and some behavior is similar to Jewish traditions. Some quarian accents are also similar to that of Roma, such as Tali's, but in the sequel it's revealed accents differ widely between ships. This is probably the only way to explain how voices like those of Shohreh Aghdashloo, Adam Baldwin, and Simon Templeman, among others, can come from the same race.
Speaking of Shepard, in the first game the player gets to craft his speech themselves by choosing dialogue options. It can make for a great Establishing Character Moment, and it's a nice touch for role-playing.
And Wrex in the third installment. Hackett also gives a very inspiring one.
RPG Elements: After all, you are playing a third-person shooter. With character customization. And experience points. And amazing plot, character development, and dialogue.
RPGs Equal Combat: Yes and no. You certainly do get exp for killing things in the first game; however, a good chunk of your early levels will come from talking to various people and scrutinizing various computers and viewpoints. The second game discards with combat rewards entirely; you get exp for completing missions, and nothing else.
The quarians are very human-like, being convergent species and all, as you find out in the third game provided you romanced Tali.
Rule 34: Inevitably. Primarily focused on the asari (as you might expect), but also includes some from the hanar. Somehow also applied to Tali, even though she's always in that suit; her dossier in the Lair of the Shadow Broker DLC logs her suit modification history, which includes nerve stimulation programs.
Hilariously lampshaded by BioWare itself in Mass Effect 2 with the alien porn magazine Fornax.
Game Salesman: Those asari/hanar porn games they sell down in Shin Akiba are really nasty.
Sure enough, fans made this magazine a reality, that can be downloaded for free.
The human trying to get a refund from a merchant in the Citadel. He returns in the sequel having finally gotten permission to get a refund... only to end up in a similar situation on the specifics of the refund itself. The player knows it's the same guy because he states it's taken him 2 years to get a refund. And in the third game, it's up to you: either make the store owner finally give him his refund, or convince the guy to stop harassing the store owner in the middle of a war. If you pick the latter, it's finally revealed what item the guy is so desperate to get a refund for: a toaster oven.
Sapient Ship: At first, the Reapers appear to be an entire species of these, identified as synthetic constructs rather than natural creatures. Then the end of the second game reveals their construction methods and it ricochets rather squickily back into Living Ship. EDI is a straight example at the end of the second game, and complicated even further in the third game, after she gains a body.
Saving the World: You get to save multiple worlds throughout the game, or at least the only parts of the world that are colonized. And of course, the entire point of the series as a whole is to save the galaxy. May be averted, though, in that they acknowledge that if they fail, there will be others who come after them. Just a looooooooooooooong time after, and those people won't have any idea what they're up against either.
Scars Are Forever: Pretty much every 'seasoned warrior' type character in the game has some form of scarring:
Shepard has at least one in default mode (for both genders), and Wrex, Zaeed, Mordin, James Vega and Garrus after his rescue in the second game have very impressive scars on their faces.
Interestingly, any scars that Shepard had gained from character creation from the first game are gone in the second for plot reasons as Cerberus pretty much had to regrow your skin from scratch. Scars being the result of external stimuli, not genetics, would logically not reform.
Scary Dogmatic Aliens: Both averted and played straight. The batarian government is fascist-like and runs primarily off of slavery, not to mention the government doesn't entirely condemn the predation of pirates and outlaws on defenseless human colonies. The quarians, on the other hand, are very much communistic: any resources beyond personal effects are available to the community at large (by necessity), and they are most definitely not enemies. If anything, the fanbase woobifies them to the extreme.
The Reapers themselves. They genuinely believe that once any organic civilization reaches a certain point, they risk creating a true synthetic race that overwhelms the galaxy choking out any possibility for the development of new civilizations, so their solution is to wipe these civilizations out once they've reached this point and preserve samples and records of their genetics, technology and cultural data.
Scenery Porn: Frequently. And for people who played the first game, the second arguably opens with Scenery Gorn, as Shepard walks through the destroyed Normandy.
The Normandy Crash Site DLC is just beautiful.
The Overlord DLC has some particularly jaw-dropping vistas. The designers were apparently so proud of it, the onboard computer of your vehicle draws your attention to it.
The third game tends more towards the above trope, but Rannoch is beautiful. It's no wonder that within seconds, Tali's already dreaming up her house there.
Science Is Bad: Although not played anviliciously straight, you still hear a whole lot more about science gone wrong than any other kind. Then again, you tend not to notice science at all until it does go wrong.
It should be noted, however, that the vast majority of the "Science gone wrong" stuff is conducted by Cerberus, which seems to have few ethical guidelines, if any.
This trope is averted (or even inverted) for universe at large. The biggest problem for the galaxy as a whole is that all the races are content to rely on technology that they found, instead of making their own FTL methods. Meanwhile, new technologies have saved Earth from environmental catastrophe, also curing most human diseases and dramatically increasing human lifespans.
Shepard: What difference does it make how you acquire a certain technology? Legion: Technology is not a straight line. There are many paths to the same end. Accepting another's path blinds you to alternatives. Nazara —- Sovereign —- said this itself. "Your civilization is based upon the technology of the mass relays. Our technology. By using it, your society develops along the paths we desire."
Scifi Writers Have No Sense Of Scale: Averted in that the game acknowledges the fact that the galaxy is quite large and that interstellar travel would be impossible without the mass relays, even with Faster-Than-Light Travel. The fact that just 35 years after the discovery of alien technology on Mars, mankind has settled a bunch of planets and is poised to take their place alongside the three most prominent species in the galaxy who have already been space-faring for over a thousand years looks like a case of this at first glance, but that's exactly the point.
Justified; this is explained by the fact that the Council has a policy of not activating any dormant mass relays unless they have a good idea of what's on the other side, since that's how the Rachni Wars got started. Humans actually got into their first inter-species war that way, when a turian patrol found an explorer fleet trying to activate a dormant relay (an incredibly stupid move from their perspective) and opened fire on them. Colonization also isn't as much of a concern for other races as it is for the humans, who are new on the scene, noted for being aggressive and expansionist, and suffering from a horribly overpopulated homeworld. While human colonies tend to be small, the aggressiveness with which humans are spreading alarms many species.
A more excusable one comes up in the descriptions of how space combat works. Lasers are effective close range weapons because they go at light speed, but are hard to focus at longer ranges, making mass accelerators more effective at longer ranges. In reality, lasers could be focused well enough that they would miss due to light-speed lag before they would cease to be damaging, and mass accelerators would be even harder to hit with.
The Codex also mentions the trope. It gets down to knife fight ranges... which are measured in tens of kilometers. As well, it mentions things like heat, projectiles traveling until stopped, and so forth as reasons why fights don't get any closer than this. Shooting the equivalent of a tactical nuke in space is bad if you miss... and there is something you don't want destroyed right behind your target. Which makes the Citadel fight stand out, if you think about it. One, the attack is coming in within visual range, meaning they're unprepared for something that close. Second, they have to worry about missed shots hitting friendlies and/or the Citadel itself.
Averted in regards to time and space when you learn about the end of the Protheans. Even with their massive power a Reaper galactic culling still requires decades to centuries to complete, just because of the size of the galaxy and how much of it they have to cover.
Sealed Evil in a Can: The Reapers are a rare case of self-sealed evil: every time they finish harvesting the current crop of civilizations, they go back into dark space and reset the mass relay system. Granted, though, they designed a can opener to let them back in anytime they wanted. Until the Protheans messed with it. There are also more than a few stories of how a certain peril was mostly dormant until someone came along and stirred it up; the most common is caches of "dragon's teeth" (husk-making devices) and other bits of Reaper technology scattered throughout the galaxy.
Sealed Good in a Can: Subverted with the Crucible, because in addition to being a weapon powerful enough to destroy the Reapers, it also has the potential to destroy the mass relays, and thus all trans-galactic society and commerce.
In the first game, one of the many random planetary descriptions involves a wealthy (and somewhat crazy) volus businessman buying an ancient crypt planet and digging it up with mercenaries, claiming to have received visions of "beings of light" designed to protect the galaxy from "mechanical demons". Considering that "demons" is a very good description of Reapers and Shepard has been on the receiving end of multiple visions courtesy of the Protheans, not to mention the fact that more than one side description turned out to be important later on, fan theory was that this would be important later on — it proves to be a Red Herring in the third game though.
Semper Fi: The Marines and the Navy are pretty much inextricable in space these days, so they are encountered everywhere throughout the series.
See the Whites of Their Eyes: Double Subversion. The fluff describes an aversion, with dreadnoughts acting like self-propelled artillery in space: keeping well back from the engagement and firing at extreme range. However nobody apparently explained that to the cutscene artists, as every starship battle shown in the series plays the trope straight. The Battle of the Citadel at the climax of the first game has it justified by having to fight within the confines of the Citadel's arms, but the space battles in Mass Effect 3 all take place in clear space.
Send In The Search Team: There's a very Heart of Darkness-esque mission in the second game involving Jacob's father. However, in a more literal application of the trope, quite a few side missions (and a few main ones) involve some person/people going missing and Shepard being tasked to go find them. And then fight his/her way out of whatever mess those people got themselves into/made.
In the third game, you repeat this trope, looking for missing krogan scouts on Utukku, this time in a Shout-Out to another 70s classic Alien.
Sesquipedalian Loquaciousness: In the first game: "I've had enough of your snide insinuations!" In the second: "I've had enough of your disingenuous assertions!" Also qualifies as Sophisticated as Hell, since your character says that right before punching a reporter on live TV.
Set a Mook to Kill a Mook: The AI Hacking ability present in the games allows you to temporarily turn mechanical opponents against each other. Obviously, the stronger the better, but some of the largest ones have immunity to abilities. In the first game, only Tali has the ability for sure; Shepard can only do it if s/he is an Engineer, or plays through a second time with a specialty. The second game has the ability more spread out, and even adds a new one: Dominate, which lets Morinth take control of organic enemies as well. In the third game, AI Hacking is tied in with Sabotage, a skill from the first game, and Shepard can learn Dominate after finishing the Leviathan DLC.
Shaggy Dog Story: The main story is fine. However, in the first game (they seem to have fixed this in the sequel), all the search and rescue side missions have you go out and search for a guy. Almost every time, the guy was already dead long before you got there. In one mission you fight your way through a base overrun by Thorian Creepers to find a handful of surviving scientists... and then if you demand they take responsibility for what they've done, they attack you and have to be killed.
Played with in the third game when you have to find the turian Primarch.
The third game's endings. It's a galaxy-wide dark age, and everyone is trapped in whatever solar system they ended up in. Especially bad for Sol, where potentially thousands of asari, turians, salarians, krogan, quarians, geth, batarians, hanar, drell, volus, elcor, and vorcha are suddenly trapped. Even if enough quarian liveships survived and can feed the quarian and turian populations and Earth can be recultivated quickly enough to feed the other populations, the volus contingent is completely hosed — they can't even breathe the atmosphere of any planet in the system.
The Extended Cut DLC makes the endings considerably Lighter and Softer: the Mass Relays are merely damaged, not destroyed, and are rebuilt, in two of the endings very quickly with Heel Face Turned Reaper assistance. The galaxy did not enter a dark age, but civilization continued on and even prospered, following a period of rebuilding and recovery.
Shocking Defeat Legacy: Both general and personal. Shanxi is the big one, and it even applies to both sides. Short story: humans try to open a random mass relay. This is illegal in Citadel space, because opening inactive relays is forbidden after past unpleasantness. Turians find them and shoot instead of talking, follow them to a colony with a good-sized fleet, and attack. The colony surrenders and the turians let their guard down, thinking they wiped out the human military. Real human military shows up and wipes out them. Turians gear up for all-out war, but the Council stops them before things go too far. The humans are sore at being attacked unprovoked, and the turians are sore that the conflict ended on a high note for the humans. Both sides are really upset, though, because it gave them a good look at how freaking strong they all are.
On a more personal level: one of the veterans of the aforementioned war was Ashley Williams's grandfather, who surrendered to the turians to save a colony, making him the only human in history to surrender to alien forces. He and his family end up being blackballed in Alliance military, preventing Ashley from moving above the rank of Gunnery Chief. The events of the first game finally break "the Williams curse" one way or another: either she dies on Virmire and is given the highest military honors by both the turians and salarians posthumously; or by the third game, she is promoted to Lieutenant Commander, and eventually becomes the second human Spectre.
Mass Effect 1 features a mission on the Citadel where some mooks take hostages in a medical bay. In a cutscene, Garrus takes out the mook holding a hostage, and after combat ends, the player, as Commander Shepard, can choose how to respond to this. Renegade Shepard's response is to compliment Garrus for taking the mook out; Paragon Shepard chastises Garrus for doing something that could have gotten the hostage killed.
This is an option to resolve the hostage crisis at the end of Thane's loyalty mission in Mass Effect 2. You can shoot his son Kolyat non-fatally, or Shoot the Hostage. The third option is a Paragon interrupt that has Shepard shoot a lamp behind Kolyat to startle him, whereupon Shepard moves in and decks him.
In "Lair of the Shadow Broker" Tela Vasir takes a civilian hostage with a similar set of options for resolving it. Among them is to have Shepard distract her while Liara throws a gorram table at her head.
Shoot the Shaggy Dog: Rana Thanoptis, the asari scientist you find researching indoctrination on Virmire in the first game, also shows up in the second game helping Okeer with his research. In the third game, if you spared her both times, a news bulletin reveals she was indoctrinated the whole time, and she was killed offscreen after murdering a bunch of politicians.
Short-Range Long-Range Weapon: In terms of gameplay, largely averted. The cover system encourages you to stay away — far away — from your enemies. It still gets played straight occasionally, but only because your melee attacks are laughably ineffective when it comes to dealing with enemies who like to get up close and personal. Also, largely averted in space combat, or so we're told. The ones we get to see happen at extreme close range, but each time they are explained.
Short Range Shotgun: Averted in the first (more so if you specialize), played straight in the second. There's even a specific "long-range shotgun" in the second game. Averted once again in the third; realizing the game balance shortcomings of the shotguns, their shot cone was narrowed to a more effective size, and their damage attenuation over range was loosened to a more merciful distance. Shot cones can be narrowed even further by installation of a "Smart Choke". Two shotguns can be used, de facto, as scope-less sniper rifles (the Graal Spike thrower with smart choke and the N7 Crusader) and one is basically a grenade launcher (the Venom shotgun).
Shoulder Cannon: Hasn't been seen but it's mentioned that the elcor's primary armaments essentially turn them into mobile heavy weapons platforms.
Hawk Missile Launcher on the N7 Destroyer in multiplayer.
Shown Their Work: The development team at BioWare went out of their way to keep the internal universe consistent, with in-depth analysis of how the titular mass effect influences society and physics, along with in-depth geological information on each planet that can be visited in-game and extensive information about each species' biology.
Sidequest: Numerous, all of them optional, though not taking many of them will make you feel like a big jerk.
The lamentable number of "Go to planet X, find bunker Y and kill everyone in it for reason Z" sidequests is arguably the only flaw in an otherwise overwhelmingly well-made game.
The Singularity: The whole purpose of the Reapers is to prevent a version of this from occurring.
Slave Mooks: Quite a few throughout the series: Husks, Collectors, keepers, the Thorian-controlled colonists, anyone subjected to indoctrination...
Even the Reapers themselves.
Slave Race: The Collectors of the second game. Some speculation is also attached to the keepers; the Protheans, at least, believed that they were another, earlier race that the Reapers enslaved to act as ambulatory Black Boxes. A particularly shocking one is the Reapers themselves.
Takes a hard turn towards cynicism in the third game. The unofficial tagline being "you can't save them all". However, espite the seemingly hopeless conflict, 3 goes out of its way to show that, when the chips are down, the average people in the galaxy are decent to good people. It shows numerous examples of selfless Heroic Sacrifices, people going through many sleepless nights in order to help complete strangers, and many other examples. And with a Paragon path, there is a true sense of unity by the end of the game across most of the species of the galaxy.
However, Vanilla Shepard (aka Blank Slate with no imported saves) takes it so that Shepard is semi-Renegade. Not complete Renegade but when faced with the major outcome of the mission always takes the Renegade option for better or worse.
All in all, the games shy away from both ends of the scale (at least when you take 3 into account). However, they tend towards idealism as a Paragon Shepard who refuses most hard choices will have higher chances of obtaining a better ending than a Renegade Shepard who shoots the dog whenever it appears necessary or beneficial.
Sliding Scale of Linearity vs. Openness: Level 5. Definitely has a direction in mind, but a lot of the missions in a given chapter can happen in any order, and almost all of the side missions are available whenever.
Sliding Scale of Shiny Versus Gritty: All over the map. The Citadel, Noveria and asari worlds tend toward the shiny end, while Omega, Tuchanka and Feros, as well as most human colonies, are fairly gritty. The Citadel itself slides from the shiny Presidium to the grittier Wards.
The Smurfette Principle: Averted with respect to your squadmates, but applied to entire species. Asari (who are technically a One-Gender Race) are the only female aliens you see most of the time, and the only other female aliens you encounter during the first two games are quarians and the rachni queen — and note that the main asari character was designed to be a love interest for male Shepards. You'll never run into a single female batarian, vorcha, hanar, drell, elcor or volus (well, it's hard to tell with the last few, but all the ones we meet have masculine voices).
Averted to an extent in the third game, where a female krogan and a female salarian put in appearances. The Omega DLC finally gives us a female turian.
Some Call Me Tim: Shows up alllll over the place. Especially with certain races (hanar, salarians) who tend to have fairly complicated names. There's even one character whose Fan Nickname really is TIM.
Also incorporated (optionally) into Samara/Morinth's loyalty mission in the second game.
Space Battle: Only a few are actually seen in the games, though they are discussed in-depth in the Codex. Space combat does largely avert most artistic license tropes about space that come up; the devs just go to a lot of effort to make sure the battles that happen in-game justifiably involve ships flitting around at extreme close range as opposed to hammering each other from thousands of kilometers away.
When you visit Ilos, the last planet in Mass Effect 1, you are able to see a ruined Prothean tower off in the distance. It seems to be identical in style to the skyscrapers on Feros, a distant planet where the environmental conditions seemed quite different. Justified in Mass Effect 3, which reveals that the Protheans were in fact a highly aggressive imperialistic monoculture more than advanced enough to build in that style anywhere they wanted. It makes perfect sense for them to have enforced a single style of architecture as a monolithic demonstration of their power.
In Mass Effect 2, Illium is similarly full of giant skyscrapers all of similar design - a literal Space Brasilia meant to demonstrate asari superiority. In Mass Effect 3 it's revealed to be a carbon copy of Thessia, and the asari to be the heirs of the Protheans in every way, including their arrogance — they're just a lot more passive-aggressive about their plans for creating a galactic monoculture.
Space Fighter: Mentioned, never seen. Their role is to harass and weaken larger ships to let their backup get the real hits in, though they can be loaded with very potent mass effect torpedoes that can apparently do nasty things to bulkheads.
Actually visible during the space battle in the first game, trailing behind the Normandy. They are just really, really small.
...and are equippable with the Thanix Cannon, according to the codex. Think about that for a second. Note that the aforementioned weapon was reverse-engineered from none other than Sovereign.
Featured more prominently in the third game.
Space Is an Ocean: As demonstrated by the Alliance Navy and the terminology used by same. The quarian fleet is also known as the Flotilla, another naval term.
Averted in other ways though. The final space battle of ME1 has Alliance ships coming at the Big Bad from all angles and notably, it's the only space borne battle depicted. In general, the game makes it a point to demonstrate that while ships are basically impossible to stop from going anywhere outside of mass relays and docking bays, it's more the political and other ramifications that are the real tricky part.
Subverted in the way the Normandy itself manoeuvres in the final battle against Sovereign. The fact that it flies up, inverts, then dives looks like a classic mistake of using a spaceship like an atmospheric fighter. Then you realise how the drives work. The element zero core modifies the mass of the ship, allowing the drives to produce greater thrust/force on the vessel. So when the Normandy does this flip, it is simply using the full potential of its element zero core to reduce mass to apply massive thrust as it 'dives'.
The nature of space is gloriously spelled out for some cadets in the Citadel in ME2.
Sergeant: I dare to assume you ignorant jackasses know that SPACE IS EMPTY! Once you fire this hunk of metal, it keeps going until it HITS SOMETHING! That can be a ship, or the planet behind that ship! It might go off into deep space and hit someone else in 10,000 years! If you pull the trigger on this, you are ruining someone's day, somewhere and sometime!
Space Is Cold: Averted. Though it only really comes up in the in-game codex, the inherent temperature of the near-vacuum, the lack of convection, and the problem of heat radiation (both in acquiring and disposing of heat) are treated correctly.
Space Is Noisy: Simultaneously played straight, averted, and even slightly justified. For the most part, the cutscenes play this almost painfully straight, although Rule of Cool is in full effect. On the other hand, it gets played with quite a bit. There are Codex entries that mention the silence of space, and several of the noisy space scenes take place in particularly thick nebulae or a planet's upper atmosphere, where at least some noise could be possible (though, admittedly, nowhere near the amount used). It's also messed with in gameplay. For example, at the beginning of the second game, during the destruction of the original Normandy, the only sound used during the spacewalk is the sound of Shepard's breathing inside his/her helmet. Also, during the battle on the docking bay in the Arrival DLC, the sounds are muffled, giving the feel of silent space while simultaneously allowing the player to hear audio clues as to what's happening.
Steve Cortez in the third game mentions turning off the sound emulators so he can watch spacecraft take off silently — implying that this trope is actually enforced in-universe, probably because hundreds of years of Space Opera movies have created the expectation in most races, as well as allowing for more awareness of your surroundings without overloading your visual cortex with data (A loud "whoosh" noise could alert you to a fast moving nearby object outside of your field of view, and is easier to quickly interpret than, say, a 360 degree panoramic display).
To a certain extent, the elcor are a Space Jew variant. Their culture and government has some noticeable parallels to rabbinic law.
The quarian trial board in Mass Effect 2 bears some striking resemblances to the Beth Din (an ancient rabbinical court during the age of the First Temple). Additionally, the prayer they recite at the beginning of the trial is almost a word-for-word translation of the Shehecheyanu.
Space Opera: An essential, played absolutely straight example.
Space Pirates: They're called 'mercenaries' more often than not, but what with all the independent hits they make, they're really this most of the time.
Space Police: C-Sec for the Citadel, and Spectres for Council space in general. The human Systems Alliance Navy also has a policy of aggressively dealing with criminals they come across, typically from orbit.
Actually, the Spectres are only charged with upholding galactic PEACE and very specifically NOT galactic law.
Space Romans: The turians. This is so prevalent it makes them the most powerful military force in the galaxy; the only reason the krogan and humans can't measure up is because the former is too disorganized and the latter doesn't have the same recruitment levels, or a strict militaristic culture.
Spanner in the Works: Shepard obviously serves as one for the Reapers. It is also discussed that the geth as a race are this as well, as they are both unique among sentient species and are developing technology outside of the Reapers' usual technological plans.
Two occur in the Citadel DLC in the third game. Brooks and the Shepard clone's plan to kill the entire Normandy crew and take Shepard's place would have gone off without a hitch... if it hadn't been for Glyph wandering around looking at elcor mating totems, and so still being free to rescue them all from the vaults. Similarly, the theft of the Normandy would have succeeded if Traynor hadn't managed to grab her six thousand credit eezo-powered toothbrush while being hustled off the ship.
Spare Body Parts: The krogan. In spades. Spare hearts, spare lungs, spare nervous systems, four testicles...
To a less extreme degree, the batarians, who only have four eyes.
Sprint Meter: Shepard usually moves at a slow jog, but when in combat (actually, only in combat) s/he can run at high speed. The brevity of the meter makes this impractical as an escape strategy, and the patheticness of the melee system limits its use as an attack. Its best use is in diving for cover.
Averted in the third game, where it's possible to sprint without fatigue during combat, and the improved melee makes it practical.
Squad Controls: Mass Effect includes very simple squad controls (hold, advance, and heel) on the Ring Menu: the Q and E keys ordered one of your two squadmates either to move in the direction Shepard is pointing or to attack a selected enemy, possibly with a special ability.
Standard FPS Guns: Though not a FPS, the games still manage to make most of the checklist. In terms of what you can personally use, you have standard pistols, shotguns, automatic weapons, and sniper rifles. The second game adds in a different flavor of automatic weapon, along with every brand of heavier equipment on the list (grenade launcher, missile launcher, flamethrower, BFG, etc.).
The geth's extremely high-speed "data pulsing" language.
The hanar communicate through bio-luminescent pulses as opposed to speech; they have to have specialized translators to vocalize to other species.
The elcor primarily communicate through speech, but convey meaning through pheromones and extremely subtle shifts in body language as opposed to tone or inflection. They have to learn to clarify what they mean with every sentence they speak.
The rachni communicate by "singing," which other species are incapable of hearing. This is never fully explained.
And though no proof is given, it is theorized that the Prothean language is this, considering how squad members react to hearing it spoken. And how Shepard reacts to having his/her head crammed full of it.
Starfish Robots: The geth have some pretty strange designs, ranging from the Armature to the larger geth platforms.
Stat-O-Vision: Used to explain why enemies are clearly labeled and marked in-game, as well as why their current shield, armor, and health status is displayed, along with your squadmates.
Stealth Pun: Several pop up in the series. Such as the Mass Effect 2 "Collectors' Edition."
Stealth in Space: The Normandy is the first ship to be able to do this. The ship is still visible, it just has all its emissions contained and is able to move without thrusters due to its drive core. The visibility is not much of a problem unless it gets very close to another ship and they actually look out of the window. Also notable that going to FTL speeds makes it easily detectable.
Joker even comments on this during Legion's loyalty mission:
Joker: You know that it's just our heat emissions that are hidden, right? They can look out a window and see us coming.
It's also mentioned repeatedly that with the dimensions of space, most people don't pay much attention to visual signs. The geth don't even have windows, considering them a structural weakness.
Steel Eardrums: Played straight for the most part; explosions don't seem to hamper the team's ability to hear or communicate in any way. Somewhat averted in the second game, with Shepard temporarily experiencing Shell-Shock Silence whenever an explosive goes off near him/her. It only lasts a few seconds, though.
Stereotype Flip: Overlaps with My Species Doth Protest Too Much on occasion; the Codex spends all of its time describing the stereotypical behavior of most species. Then you actually go out and run into lots of people who don't conform to those standards.
Sticks to the Back: Pistols and submachine guns have holsters, but everything else folds up and packs onto the back. Justified as mass effect field emitters can be seen on the back of armor and cloth uniforms exactly where the weapons "rest."
Storming the Castle: Present in the first two games. The attack on Fist's bar and the Virmire assault from the first game, and the entire point of the second game is recruiting soldiers to attack the Collectors on their side of the Omega-4 relay.
And then comes the third game, which features both you and the main antagonist factions engaging in this.
Storyboarding the Apocalypse: In a way. The first game gives the general details of what happens every time the Reapers roll around, including timing and general behavior. But not everything was revealed, making the discovery that the Reapers took time to enslave the Collectors and apparently harvest said beings for making baby Reapers, as opposed to simply killing them all, a bit of a shock.
Shepard is often portrayed in the default Soldier class, which by the game's own lore makes the most sense in explaining his prowess in combat. This is particularly true in the first game where it is hard to justify how Shepard can match an asari in biotic power or a quarian engineer in Tech skills.
Liara T'Soni is the only Love Interest who can be romanced in all three games, by both genders, and cannot die under any circumstances except for low-EMS ending of the final installment.
In Mass Effect 2, during Samara's loyalty mission, you can choose to kill Samara and recruit her target Morinth if you want to and Morinth will be a loyal squad mate for the rest of the game. The favoritism doesn't show up until Mass Effect 3. If Samara survives her loyalty mission and the suicide mission, then in ME3 she will show up when you do the Ardat-Yakshi monastery mission and it will make that mission a much richer experience. If Morinth survives said events of ME2, all you get is an email from her at the beginning of ME3, and then during the final mission, you fight her as a Banshee, kill her, and move on.
The early Freedom's Progress mission in Mass Effect 2 has the player choose between turning Veetor over to either Cerberus or Tali. If you choose Tali, Veetor shows up at Tali's loyalty mission later to help the two of you out. If you choose Cerberus, the Veetor subplot basically ends right there; Shepard loses that much rapport with his longtime partner Tali, and over nothing, since Veetor's interrogation at the hands of Cerberus fails to turn up any useful information.
Story to Gameplay Ratio: Definitely more to the Story than Gameplay side, but there's still an equitable amount of both. It starts to tip more towards gameplay if you skip the dialogue.
And more towards story if you take the time to read every codex entry and log.
The third game lets you pick which side of the ratio you want to be on. You can play normal, in which the game is presented as the developers intended. You can play gameplay, in which the cutscenes/dialog are shortened and a lot of the choices made automatically while the combat is made tougher. Or you can play story, in which the combat is what's cut down and made easier.
Introduced in the second game, vorcha. But the trope is best exemplified by the salarian Mordin Solus.
Streaming Stars: Averted. Plenty of light going by, blueshifted by the speed of travel, but the stars stay right where they are.
Stripperiffic: Three of Shepard's companions have impractical high heels and skin tight outfits. The law enforcer (Asari Justicar) looks like this. Lampshaded in Miranda's case by several NPCs including two of Normandy's engineers and an asari mercenary who tells her she's waiting for Miranda to get dressed before the shooting starts. And then there's EDI.
Subspace Ansible: The primary form of communication is using photons ferried through the mass relays, which results in limitation of bandwidth. Quantum Entanglement Communicators are another form of communication, with its own bandwidth limits plus it only ever connects two places — so if you do not want to talk to somebody special they are of no use whatsoever. They are more prevalent in the third game, though.
Even more so, The Catalyst, and by extension, the Leviathans.
Suicidal Overconfidence: For the most part, played straight; a massively large number of mercenaries, pirates, and private security teams seem to think they can take on the Normandy's crew. There are a few places where Shepard can point out that this didn't go too well for the last few hundred or so people to think like this and urge them to reconsider. Most of the time it works.Sometimes it doesn't.
Lampshaded during the Mordin loyalty mission:
Weyrloc krogan: Run away now while you still can!
Shepard: I don't know, I might trip on the dozen or so krogan I had to kill to get here.
Hilariously lampshaded in the encounter with Niftu Cal.
In the third game, if Shepard acts very confident about defeating the Reapers, many characters will think this trope applies to Shepard. Which it might.
Superior Species: Though they have all the hallmarks, the asari rarely actively play this trope straight. Which is good, because it's averted more often than not, and even deconstructed in the second game. The Reapers, on the other hand, play it straight all the way.
Not to mention the reveal in the third game that asari superiority is largely due to the Protheans grooming them during their primitive stages to be the current cycle's hope against the Reapers.
To a certain extent in the third game; aside from the Reaper ground troops, the Cerberus mooks in the third game are enhanced by Reaper cybernetics.
Superpower Russian Roulette: The only way to get a biotic is through pre-natal exposure to eezo. However, this has a higher chance of causing brain cancer than granting people gravity-controlling powers.
The Infiltrator class has its own version; when looking down the scope of a sniper rifle, time slows down for a few seconds, giving ample opportunity for headshots. In the third game, this ability is still present, but other classes can have them via a sniper rifle mod.
In the second game, a properly upgraded Biotic Charge gives the Vanguard a few seconds of time dilation after use. In the third game, this applies regardless of how the power is evolved.
Super Soldiers: Every Alliance marine fits the definition of this trope in the ME universe, having received numerous genetic tweaks as part of standard training, though specialists get more fancy enhancements. There are more fantastic examples, though, mostly in the second game, notably Shepard, Miranda, and Grunt. It is unknown what the tweaking policy is for other species.
And in the third game, we learn that Cerberus has its own ways of doing this.
Surprisingly Elite Cannon Fodder: Mass Effect 2 could be seen this way as a serious example; a Ragtag Bunch of Misfits sent away on an admitted suicide mission, the leader of whom the Council has tried to wash their hands of. Whether they do end up being mere cannon fodder is up to Shepard.
Survivor Guilt: Not as rampant as someotherissues common amongst Shepard's team, but each one still has members who feels this. Like Shepard him/herself. Or Ashley. Or Kaidan. Or Jack.
Han Olar could be the most profound example of this in any game ever.
Garrus, too. In ME2, Liara shows signs of this in regard to Feron, before it's revealed that Feron is alive.
Starts to weigh heavily on Shepard in the third game, and Admiral Zaal'Koris.
In the third game, Liara's Survivor Guilt over the fall of Thessia pushes her into nigh Heroic BSOD territory. Player choice determines whether Shepard pulls her out of it or joins her in it.
Take Cover: The game's combat system utilizes extensive cover, like most Third Person Shooters.
Take Your Time: For the most part, this is played absolutely straight. Anytime you receive a distress call, are informed of a "desperate" situation, or have been sent an urgent communique about something that needs to be dealt with right now (like tactical missile launches, falling asteroids, or falling ships), go ahead and ignore it. It'll still be there in five hours. Memorably subverted in one instance in the second game, however: the longer you wait after the Collectors abduct the crew of the Normandy, fewer of them will be alive when you rescue them.
Averted twice in Mass Effect 3: if you don't complete the evacuation of Grissom Academy within a certain amount of time, Cerberus will kill most of the students and you'll have to face an indoctrinated Jack at Cerberus Headquarters. Also, failure to disable the Tuchanka bomb will cost you heavily when it comes to krogan war assets.
Talking Lightbulb: Both quarians and volus have this built into the "mouth" area of their suits. Why has not been explained, nor does it entirely sync up with their speech.
The reason the light blinks is because if more than one quarian, volus, etc., is present, its helpful to know which one is speaking. Sure, you can also do that off of voice recognition, but that's only if you know them.
Talking Is a Free Action: As in all BioWareRPGs, though not quite as bad as in others. Most of the time, if something urgent is going on, the conversations will be short, and you can't start a conversation in the middle of a gunfight. However, certain sequences, like confronting Saren on Virmire, occur while nuclear weapons are ticking.
Lampshaded in the sequel a couple times. Shepard can bring up inane topics a few times in the middle of critical situations, and the character s/he's talking to will call him out on it.
...or be zapped with electricity, in one particularly uncomfortable interrogation in the Shadow Broker DLC. At least the poor victim manages to take it all in stride.
Terminally Dependent Society: The quarians. Most of their food comes from a few agricultural liveships. These ships are kept at the center of the fleet, and are so fragile they're most of the reason for why quarian military forces will only transmit one warning before blowing your ass out of the sky. Also, galactic travel is impossible without the mass relays, all of which are under the control of the Reapers.
Terraforming: Mentioned but rarely, if ever, seen, mostly because it's hideously expensive.
Terrified of Germs: The quarians, courtesy of having immune systems that are slow to adapt. Understandable, though; there's at least one mention of a quarian killed by... a cough.
Tali: Shepard, if I don't wear a helmet in my own home, I die! A single kiss could put me in the hospital! Every time you touch a flower with bare fingers, inhale its fragrance without air filters, you're doing something I can't.
Tertiary Sexual Characteristics: Quarians have several suit differences between male and female: females generally have a "girly" color scheme and have veils on their heads, males have hook-like things that extend off their masks, and so on.
Thanatos Gambit: The sole survivors of the Prothean race sabotaged a Reaper trap in the hopes that it would give future species the chance they never had. It was a one-way trip and they all died of starvation, but their sacrifice paid off thousands of years later.
That Came Out Wrong: Almost everyone has at least one of these, but the most common (and popular) come from Garrus, Tali, and Liara.
Garrus: You know me. I always like to savor the last shot before popping the heat sink. (Beat) ...Wait. That metaphor just went somewhere horrible.
Elcor have extremely monotone voices because they communicate their emotions through pheromones and other means too subtle for other species. To get around this they state their emotions while speaking, such as "Delighted: welcome." This is later used to humorous effect in a random Citadel radio announcement when a human patron of the arts says he's organizing an all-elcor run of Hamlet, the entire point of which (as far as human audiences go) is to filter out all the emotional overtones to the Danish Prince's behavior.
The elcor bouncer at Afterlife when a customer threatens to force his way past him: "With barely constrained menace: I would like to see you try."
An elcor on the Citadel in 2 is accused by his companion of hacking his translator to lie about his speech conditionals. His response: "With a sincerity such that doubt would be considered deeply offensive: No".
Averted in one instance by the elcor ambassador in Mass Effect 3: He doesn't use a prefix, stares downwards, and sounds like he is about to cry.
That's No Moon/Reality Retcon: The Solar System's mass relay was Charon. The rock and ice seen in the 21st century were just a concealing shell.
As of the second game, Shepard has met two Reapers, Sovereign and Harbinger. While those are not their real names (at least, the first one isn't), they are both words you would most likely see used to refer to a hero or some other position of greatness.
In other news, Systems Alliance dreadnoughts are named after mountains on Earth (e.g. Everest, Kilimanjaro). Cruisers are named for cities (New Delhi, Tokyo). Frigates are named after battles (Iwo Jima, Hastings, Agincourt, and, of course, Normandy). Carriers buck the pattern; they're named after historical figures from human history (Einstein, Hawking).
All the Prothean VIs have names beginning with "V" (Vigil, Victory, and Vendetta).
Most weapons share a common theme: shotguns tend to be named after swords (Katana, Scimitar, Claymore), SMGs after insects (Hornet, Locust). However, it's more a tendency than a constant and mostly limited to human weapons. Sniper rifles have a similar theme (the Widow/Black Widow, the Mantis) but it's not a constant (Vipers are not bugs).
There Are No Therapists: Averted. Repeatedly. The most messed up people in the game, should you so choose, are quite explicitly shipped off for therapy. And the second game even has its own therapist on your ship. (Perhaps inevitably, said therapist is the only one to visibly have problems adjusting after nearly being turned into Reaper Goo in the suicide mission, assuming she lives.)
In the third game, you can overhear a therapist talking a PTSD soldier through her experience in the Reaper war. If you follow their conversation all the way through, the soldier disappears from beside the therapist, and it's left up to you to authorize her incessant request for a gun. If you oblige her, she uses it to kill herself, traumatizing the hospital staff and adversely affecting certain war assets.
Third-Person Person: The hanar speak like this, since their culture believes that using first person in public is rude. A Colonist Shepard has an exclusive sidequest in the first game involving a human woman who refers to herself this way.
Most notable in the first game with the Thorian, Vigil, and the Reapers. The page-quote from the trope page in fact originates from Sovereign, the first encountered Reaper.
The Catalyst, the intelligence that built the Reapers, in the third game. And by extension, the Leviathans, the race that created the Catalyst AI in the first place, and from whom the first Reaper was modeled after.
Timed Mission: Contains a few, but they're really not too difficult, and for most of the missions you can take as long as you need. They also make for some of the more memorable missions.
Some of the notable ones include: in the first game, rescue Tali (or she dies); in the second game, the Thresher Maw, which you only need to survive for five minutes — Bonus Points for actually killing it. In the climax of the second game, you have to prevent your tech specialist from being killed in the vents - you have a timer for each switch that must be thrown.
And then there are the challenges in the Mass Effect 3 multiplayer mode.
Averted with many other missions - whenever you hear that "we need to hold this position until X", chances are that X happens exactly when all enemies are dead.
Title Drop: As seen in the page quote, "mass effect" is an ability of element zero to increase or decrease objects' masses depending on the polarity of an electrical charge via dark energy. It is the basis for the technology of interstellar civilization, and is mentioned to be such.
Token Romance: The romances. What happens on the Normandy, stays on the Normandy.
Of course you can avert this as the romance is entirely optional.
Can also be averted in the Citadel DLC, where Shepard is given an apartment, and will wake up with their LI there after the party; Fem Shep can also go on two dates with Garrus on the Citadel in the third game. Shepard and their LI also discuss plans to settle down after the final battle, though both are aware it probably won't happen.
Touch Telepathy: The Asari need physical contact to Mind Meld. They can share memories and emotions this way, but it's also how they reproduce.
To Win Without Fighting: The Charm and Intimidate conversation options. The earliest example occurs during a Mexican Standoff in the first game. Either Paragon Shepard points out that this would be a good time to leave, or Renegade Shepard points out that he/she's killed about fifteen well-trained guards to get there.
Translation Convention: We hear a Prothean recording on Ilos speaking in English, but Shepard is the only character who understands it because of the Cipher. When the party meets Vigil shortly afterward, however, he addresses them in English Galactic, having monitored and analyzed their radio communications. Note that the Translator Microbes present in the setting means that the entire party would thus understand him even if you take alien allies to Ilos.
In the Redemption comic, Translation Convention is both referred to (it starts by talking about Omega station and how it also means something final in alien languages, and a mention of how a phrase may not have translated properly) and played straight when Liara mistakes the Illusive Man for an "Elusive" man.
Translator Microbes: As explained in the codex, alien languages are translated real-time by portable computers or sub-dermal chips, without which intergalactic culture would be a far more difficult affair to sustain.
Trial-and-Error Gameplay: Since dialogue options do not reflect exactly what Shepard will say or do, picking any option is often a leap of faith that leads to an undesired result. Such unwanted responses tend to result in many players jumping to the Pause menu to reload their last save.
For example, one option for a male Shepard to resolve the Ashley/Liara love triangle is to suggest a threesome. Ashley dumps you and leaves in a huff, and the game treats it as if you'd chosen Liara. There's no real way to predict this outcome.
A more infamous example involves the Asari Consort. When you complete her mission, she rewards you by giving you a "gift of words," i.e. a prophecy. If a Shepard of either gender responds with "That's it?" a sex cutscene is triggered. This gave rise to a meme, "The Consort raped me!"
Tribal Face Paint: The turians all have facial markings defining the wearer as a member from one of the colonies where they were born. Which all stems from some sort of civil war.
True Companions: The crew of the Normandy in all three games is a Band of Brothers, brought together principally by Shepard and hir mission. More than half your crew in the third game were with you in the first and their conversations reflect this. The krogan species generally forms these and call them 'krannts'.