Mass Effect: Andromeda, which was developed by Canadian studio Bioware and is out next week, is the latest in a series of sprawling sci-fi action-adventure games.

Trailers and previews promise multiple planets to explore, missions to complete and mysteries to uncover.

But for many players who flocked to the series in the first place, all of this is secondary to the real reason they became fans: getting hot and heavy with your crewmates (human or otherwise).

The first three Mass Effect games — released in 2007, 2010 and 2012 — put you in the shoes of Commander Shepard, who leads a team of humans and aliens to explore, and eventually save, the Milky Way. (Players can choose at the outset whether to play Shepard as a man or a woman.)

Meg Smitherman Mass Effect tattoo

Mass Effect fan Meg Smitherman shows her tattoo of the female Commander Shepard, known as 'FemShep' to her fans. (Meg Smitherman)

Think of it as a modern, video game equivalent of Star Trek.

While players could embrace their Captain Picard-like philosophical side, negotiating with aliens and navigating interplanetary political alliances, they could also channel their inner Captain Kirk — by romancing one or more of the supporting characters.

Meg Smitherman is one of the many gamers who started playing Mass Effect because of the romantic storylines rather than the action, which makes up the bulk of the games' run time.

She says she plays all the games on the "Casual" setting, which is the lowest level of difficulty.

"The action is fun for me, but I'm gonna get through it so I can continue the story and the characters' development. That's the core of the game, for me," she says.

If you think playing Mass Effect on its lowest difficulty implies Smitherman isn't that hardcore a gamer, think again — she has an elaborate half-sleeve tattoo of Commander Shepard on her right arm.

Mass Effect Andromeda squad shots

The main cast of Mass Effect: Andromeda. As Ryder, centre, players can have romantic relationships with crewmates or other non-player characters. (Bioware)

Mass appeal

A major part of the appeal is the games' branching dialogue paths. Players could choose Shepard's lines throughout the game, directing whether he or she becomes a peacemaker or aggressor (Paragon or Renegade, in the game's lingo).

It also meant they could choose to pursue romantic relationships with one or more characters, or none at all.

Actor and comedian Mark Meer, who voices the male version of Shepard, credits Bioware's writing team and his fellow cast mates for "for crafting complex, interesting characters" that players can get to know better.

"They made characters that you wanted to get to know, whose pasts you wanted to learn and whose futures you wanted to shape."

It wasn't the first game in which players could build relationships with their characters — it wasn't even Bioware's first, as they experimented with it in Baldur's Gate 2 (2000). But it was one of the earliest examples where the main character, who the player controls, was fully voiced.

"Games before that, usually you just got a block of text and you'd just choose which text you'd respond with and click on it. And you'd hear the response of the other character, but not your own. By having a voiced player character, it became like a movie," Meer explains.

Mark Meer Skype Mar17

Actor and comedian Mark Meer voices the male Commander Shepard in the original Mass Effect trilogy. (CBC)

He calls it a "heady responsibility" to be the avatar of millions of players' amorous advances, one he shares with Jennifer Hale, who voices Shepard's female counterpart.

"It's also an interesting situation to be in as an actor. Rather than, say, having a viewer fall in love with your character, you've got a player romancing a second character, using your character as a medium," he says.

Smitherman says her favourite romance is with Garrus, a former paper-pusher turned vigilante sniper and eventual confidante. Garrus is also a turian, an alien race resembling a "humanoid bird or raptors" with their long, lanky limbs and mandibled mouths.

"He's definitely a weird-looking alien. He's a giant bug, you know?" says Smitherman. "But there's something about him. He's really good at what he does, he's sarcastic, funny and a little self-deprecating. He's just a really good guy with a great personality that you kind of overlook the bug thing. It becomes attractive, almost."

She also credits Garrus' voice actor, Brandon Keener.

"He has a really hot, intense voice."

Mass Effect Garrus

Shepard and Garrus have a moment. (Bioware)

From sex scandal to selling point

Mass Effect wasn't the first game to feature sex scenes, but it sparked a moral panic in the mainstream news.

Shortly after the first Mass Effect game hit stores, a Fox News panellist likened it to hardcore pornography. Title cards for the TV segments read "SE'XBOX" and said the game included "full digital nudity and sex."

In reality, the sex scenes that occurred after you built a romantic relationship with a character lasted about 30 seconds and didn't push the envelope beyond what you'd see in your average PG-13 action flick.

Publisher Electronic Arts defended the game, calling the report inaccurate, and the panellist who originally made the claims later apologized, admitting she didn't watch or play the game before making her comments.

Fast forward to 2017 and the series' reputation has been buoyed rather than constrained by its intimate interludes.

"Now it's become Bioware's thing," Smitherman says, "There are really no other big gaming companies doing romance at such a complex and deep level, in terms of it being such a huge part of the game, and being so well interwoven with the plot."

The creators are leaning into it, too.

"Even aside from what Mass Effect has become, I think it just makes sense," Bioware creative director Marc Walters told the gaming site Game Informer.

"You put people in these stressful situations. There should be tension. There should be love. There should be all of those ranges of emotions with the characters."

Walters promised that Andromeda will include more varied and nuanced romantic options than before. One crewmate might want a long-term relationship, while another might just want a one-night stand. Some might not be interested in romance at all.

The creators aren't afraid of fans' raunchier interpretations of the characters' love lives, either.

When a fan asked about the sexual opportunities in Andromeda, producer Michael Gamble answered, "the banging is pretty good."