A surprisingly small team built the best game of 2015

"Fallout 4" is a massive game. You could easily sink hundreds of hours into exploration and creation, to say nothing of the game's main or side stories.

And that's why it's so incredible that a team of just over 100 people created it.

The male version of the main character in "Fallout 4," with "Dogmeat" (the dog!).
Bethesda Game Studios

The creative director of "Fallout 4," Bethesda Game Studio's Todd Howard, explained the process of creating the massive, fascinating game in a phone interview this week with Tech Insider.

"It actually started right after 'Fallout 3,'" Howard said, in reference to the beginning of development on "Fallout 4."

That's late 2008, when Bethesda Game Studios' last "Fallout" game — "Fallout 3" — launched for the Xbox 360, PlayStation 3 and PC. "Fallout" games take place in a post-apocalyptic world 200 years in the future where humans have destroyed civilization with nuclear weapons.

"I knew I wanted to start the next one in the past," Howard said. "I was really excited about showing the world before the bombs fell. And that moment of running to the vault and getting in as the bombs fall, and then emerging much later. So that was kind of the initial nugget, and that was in 2009."

That initial germ of an idea made it through the six years of development to the final product.

A scene from the beginning of "Fallout 4," set in 2077 (before the nuclear bombs fall).
Bethesda Game Studios

Much of the team that worked on the previous "Fallout" game remains at Bethesda Game Studios to this day.

"Istvan Pely, the lead artist on 'Fallout 3,' he rolled right off of the DLC [downloadable content] into 'Fallout 4.' The first thing he built was the power armor," Howard said.

Following the launch of "Fallout 3" in late 2008, Bethesda Game Studios created a variety of "downloadable content" for the game — essentially major gameplay expansions to the original game: new missions, storylines, characters, etc. The studio is working on similar support content for "Fallout 4," to be released at some point in 2016, but hasn't given any details just yet.

So, while some staffers (like the aforementioned lead artist) and a small crew of programmers got to work on creating "Fallout 4" way back in 2009, the rest of the studio began working on "The Elder Scrolls: Skyrim" (referred to more simply as "Skyrim").

A screenshot of "The Elder Scrolls: Skyrim," which came out on Xbox 360, PlayStation 3 and PC in 2011.
Bethesda Softworks

Howard described that process of developing two blockbuster games at once, with a crew of around 100 for both, as a careful balance:

We're always kind of designing one game while in production on one, and talking about one. Staggering our development somewhat. When we're really working on a game, it takes everybody's attention. We'll discuss the other one. We'll kick it around over lunch, and then we'll have concept artists or other people start on stuff. So "Fallout 4," we kind of picked away at things, and concepts, while we worked on "Skyrim," but we were very focused on "Skyrim." But once "Skyrim" was done, we'd had a couple "Fallout 4" things ready. And we knew what we wanted to do — what the big things would be in the game. And we just started attacking all of those things at once.

With the launch of "Skyrim" in 2011, Bethesda Game Studios set out to support the game with "patches" (updates to fix issues with the game) and downloadable content. Over the next two years, the studio gradually moved from "Skyrim" to full-on "Fallout 4" development.

By 2013, the whole team was working on this year's big game.

"It wasn't until the middle of 2013 that the whole team was on "Fallout 4," Howard said. "Usually it'll start with most of the programmers, some artists and designers, starting to build the tech, build the first areas we're gonna play in. And once we really know this is how we're building content for the game, that's when everybody comes on."

It was during the sprint from halfway through 2013 to the halfway mark of 2015 — just two years — that the game came together. That's when the game was first shown off, during a Bethesda press conference at the game industry's annual trade show in Los Angeles: E3.

Bethesda Game Studios' Todd Howard introduces "Fallout 4" for the first time at E3 2015 in Los Angeles, CA.
Bethesda Game Studios

Just before and following the game's big coming out party in June 2015, the game was complete enough to start troubleshooting for the its impending November launch.

But "Fallout 4" is a massive game with near-endless variables.

It's nearly impossible to identify every possible scenario in such a game, reproduce it, and fix it (all without breaking something else in the process). The massive, incredibly difficult task was given to the game's publisher, Bethesda Softworks, and its 100+ person team of quality assurance testers.

You read that correctly: "Fallout 4" was tested for quality by a team nearly the same size as the development team.

"It's really not till the last probably...six to seven months are a pretty big crunch on them breaking the game and us fixing it," Howard said. "And every day is a new adventure. Something new is gonna happen."

But even with that large of a staff testing "Fallout 4," it's impossible to make it perfect. There are simply too many variables.

One of the many player-created "settlements" in "Fallout 4."
Bethesda Game Studios