Exactly how big is Fallout 4?

A scene from the video game Fallout 4.

She's not sure, but Courtenay Taylor believes she set a record while working on Fallout 4.

"I think it's the most lines a protagonist has ever had [in a video game]," says Courtenay Taylor, a San Francisco voice actor who spent two years recording 13,000 lines of dialogue for the open world shooter.

"I thought it would be 10 or 15 sessions. I did somewhere around 55. It kept going and going. I was like, 'Wow, it's never going to end.' I just didn't want it to be over."

Fallout voice actress Courtenay Taylor.

The massively anticipated RPG from Bethesda is the follow-up to 2008's much-loved Fallout 3 and sees gamers surviving in a futuristic version of Boston that's been devastated by a nuclear disaster and populated by mutated, deformed animals.

Much of the game's appeal is in its vibe.

It mixes 1950s Americana with burnt-out Cadillacs lining the streets and big-band music soundtracking fight scenes, with futuristic technology.

That includes the Pip Boy, a giant wrist watch that players can use to upgrade skills and switch inventories.

Special editions of the game come with a real-life Pip Boy that players can download an app for and use with their phone. With the ability to modify weapons, craft a shelter and customise outfits and armour, Fallout 4 offers endless options for fans who want to immerse themselves in Fallout's dusty, sandy world.

Courtenay Taylor's character from the video game, Fallout 4.

Taylor, who has voiced characters in Mass Effect, Star Wars and Resident Evil game series, says Fallout fans are definitely the quirkiest she encounters.

"Fallout fans have a whacky sense of humour. You say one crazy thing, and they'll turn it into a [meme].

"Fallout is for people who want to create their own universe. The weapons, the armour ... your character is different to everyone else's.

"It takes a particular brain to play Fallout. A massive, crazy, supersmart brain."

What: Fallout 4
Platform: PlayStation 4, Xbox One
Rating: R18
Release date: Out now