There is perhaps no more decadent sight in gaming than a well-executed Earth Defense Force attack. Maybe you’ll fire your jetpack northwest, maybe you’ll fire your rocket launcher southeast, and maybe you’ll detach 10 giant alien ant thoraxes from their abdomens all in one move. Maybe you’ll destroy a skyscraper in the background at the same time.

Sure, none of this will look particularly pretty. It might well be happening at single-digit framerates. But that’s all part of the fun.

The Earth Defense Force series is now five core games deep, and this week sees the release of its most advanced entry yet. Earth Defense Force: Iron Rain is a second attempt at adapting the series’ esoteric charms for a Western audience. But Earth Defense Force has perhaps the most humble origin story of any long-running game series around today.

I recently spent time with developers who were there at the start, as well as those who’ve been working on Iron Rain, and all were happy to speak candidly about how Earth Defense Force became an improbable global hit.

A simple start

The Earth Defense Force series is often compared to B movies, which isn’t surprising given the age-old story it tells about flying saucers attacking humanity. But the comparison is even more apt when you look into the series’ origins. The entire franchise owes its existence to a range of ultra-budget releases called The Simple Series from D3 Publisher.

The Simple Series was a fixture of Japanese game stores from the late ’90s until the early ’10s. Each platform had its own numbered line and fixed price point, so while the range started at 1,500 yen (~$15) on the original PlayStation as The Simple 1500 Series, the price went up 500 yen for The Simple 2000 Series on PS2, and then again for the PSP Simple 2500 Series.

Early Simple Series releases tended to be rudimentary adaptations of classic games like shogi, chess, or billiards. But by the end of the original PlayStation’s life, the Simple 1500 series had expanded to cover dating sims, RPGs, and side-scrolling shooters. Some of the games managed to pick up cult followings, but the goal of the series was very much about releasing games as quickly and as cheaply as possible.

“Believe it or not, we had to release 30 to 40 Simple titles every year back then,” says Nobuyuki Okajima, Earth Defense Force’s series producer from the first entry. Okajima started working in PR at D3 but became the lead Simple Series producer around the 20th release, which was creatively called THE Puzzle. He cites THE Sniper, the 56th game in the series, as a personal favorite from this time.

“We couldn’t add any features or extras — instead, we had to think about what we could cut from the original concept and what would be the main focus of the game design that we could polish.”

The idea for the first Earth Defense Force game came from Sandlot, a small developer based in Tokyo. “Since we were making so many Simple Series games, we knew at some point we’d be out of ideas, so it was good timing,” says Okajima. “We had successful games like [action game] Oneechanbara, and other companies like Sandlot started pitching and giving us new ideas from outside of D3P, and Earth Defense Force was one of them, so we felt lucky.”

Sandlot is one of many companies started by former employees of Human Entertainment, which closed around the turn of the millennium and was best known for the Fire Pro Wrestling series. Spike, the later custodian of those games, formed around the same time and eventually merged with visual novel studio Chunsoft. Another notable alumnus from Human is Goichi ‘Suda51’ Suda, who founded Killer7 and No More Heroes studio Grasshopper Manufacture after working on Fire Pro Wrestling.

Sandlot’s initial speciality was games inspired by tokusatsu, the Japanese genre of films and TV that uses a distinctive style of practical effects to bring giant mechs and monsters to life. Before Earth Defense Force, the developer’s biggest release was Robot Alchemic Drive, known as Gigantic Drive in Japan. The game’s unusual design saw you remotely control a huge robot from the ground, switching between perspectives.

“As a team at Sandlot, we used to make a lot of mech and robot games,” says director and planner Takehiro Homma. “A lot of fans recognized this and saw us as a maker of mech games, which we didn’t like much — we wanted to explore more, and we wanted to try more interesting game designs utilizing what we’d done. So we presented the Earth Defense Force concept to Okajima-san because we wanted to try something different.”

Earth Defense Force nearly ended up becoming a mech game anyway, though. Sandlot’s original pitch included ideas for both the Earth Defense Force formula that has survived ever since, as well as the robot action that the company had previously been known for. Homma says Sandlot wanted to show that it could come up with something new. But D3P wasn’t so sure.

“Back then at D3P, we used to vote in the office on which new titles to pick,” says Okajima. “The main point of contention was that the Simple Series has to be very simple, but the concept wasn’t that simple — it was both a shooting game and a mech game. It was a 50/50 split — half of the team turned it down, so we ended up asking Sandlot just to make the game that became Earth Defense Force.”

No time, but no notes

THE Chikyuu Boeigun, which translates as “The Earth Defense Force,” was released in summer 2003 as volume 31 of the Simple 2000 Series for PS2, following an intensely accelerated development period of just six months. With two months set aside for testing and debugging, the actual game itself was made in just four, with no more than 12 people working on the entire project.

“We couldn’t add any features or extras — instead, we had to think about what we could cut from the original concept and what would be the main focus of the game design that we could polish,” Homma says. “That was the most challenging part about making the first Earth Defense Force.”

“However, one good thing about that project was that we had full creative control in those four months,” Homma continues. “When you look at regular game development, you’ll probably have regular weekly or monthly meetings with producers and other people to talk about what to fix based on feedback, but for this project we never even had a meeting with Okajima-san on the publisher side. We could do anything we wanted for this game back then, which was amazing.”

Sandlot’s developers describe a tough but rewarding work environment, where restrictions on time and budget demanded creative solutions. For example, the giant ants that remain the series’ iconic cannon fodder to this day were chosen simply because nature had already done most of the work. “Basically within four months there’s no time to design original characters, so you take something that exists around you everywhere,” says art director Masatsugu Igarashi. “We picked up reference images from books and used them to create the enemies.”

“We actually spent a lot on the marketing and PR budget just because the marketing person at that time liked this franchise.”

“We couldn’t approach development in a traditional way, with a separate programming team and game design team and art team and so on,” says programmer and director Toshio Noguchi. “So we had to change our process to doing everything at the same time, with everyone overlapping and helping each other to minimize the working process. That’s one of the best ways to come up with good ideas.”

“I want you to know that we really enjoyed it,” Homma says. “It wasn’t painful; it was really fun to work on this. With a lot of people and money, of course you can make good games more easily, but the restrictions and creative freedom gave us a challenging situation that we could enjoy over the four months, and it came out pretty well.”

While Sandlot was happy with its final product, Homma said the company wasn’t sure whether Simple Series customers would appreciate its qualities. Ultimately, though, THE Chikyuu Boeigun sold more than 150,000 copies after Okajima convinced D3P to spend the whole marketing budget for all four Simple Series releases that month on this game alone. Okajima says the performance ended up well above average for the series.

Due to THE Chikyuu Boeigun’s success, D3P and Okajima wanted Sandlot to work on a sequel right away and attempt to create a Simple sub-series. Sandlot was initially tied up with a return to the world of giant robots, however, making a game for Bandai Namco based on the Tetsujin 28-go manga franchise. Once Sandlot’s schedule freed up, though, the company returned to start work on THE Chikyuu Boeigun 2.

With a slightly longer development time and the fundamental framework for the game already in place, Sandlot was able to focus on adding features and content to the sequel. “It was a little easier because it was the same hardware and we had the engine and game design already, so we were able to jump in right away,” Homma says. THE Chikyuu Boeigun 2 featured almost three times as many missions, added spiders, and perhaps most notably marked the debut of the jetpack-equipped playable female soldiers.

THE Chikyuu Boeigun 2 turned out well, and D3P got behind it with a bigger push than its predecessor. “We actually spent a lot on the marketing and PR budget just because the marketing person at that time liked this franchise,” Okajima says. The effort paid off with sales of more than 320,000.

Courting North American players

D3P had a hit on its hands, but it also faced a problem: It wasn’t able to sell the games in North America. The first game did get a little-heralded PAL release called Monster Attack, and the second game saw some belated minor success in Europe as Global Defence Force, but Sony’s North American arm was less forgiving.

“They didn’t want cheap games, or games with bad graphics, or games with unstable framerates, and so on,” Okajima says. Even in the PAL releases, D3P was forced to remove Japanese dialogue due to platform restrictions, a situation that Okajima described as “almost unacceptable.”

This predicament was what led Sandlot and D3P to take a surprising turn for the next game in the series, 2006’s Xbox 360-exclusive Earth Defense Force 2017. (It was called Chikyuu Boeigun 3 in Japan and released at full price, no longer part of The Simple Series.) The Xbox brand’s struggles in Japan are well-documented, but back then D3P saw it as the best chance to make a go of Earth Defense Force in the West.

“It’s actually a simple story — we couldn’t sell this game internationally on PlayStation, so that’s why we decided to develop it exclusively for the Xbox 360,” Okajima says. “Back then, Microsoft used to tell everyone that they weren’t going to give up on making the Xbox a success in Japan, so many companies including us hoped that the sales would increase and help our sales of Earth Defense Force overall.”

The bet paid off. Earth Defense Force 2017 sold more than 200,000 copies between North America and Europe, as well as 130,000 more in Japan. While that latter figure represented a decline in sales for D3P’s domestic market, Okajima says the performance was amazing given the active install base of just 200,000 consoles at the time — more than three in five Japanese Xbox 360 owners bought the game.

On top of that, Earth Defense Force 2017 brought in far more revenue for D3P because it was no longer sold as a budget title. “As a producer, it was a huge moment for myself when we released a full-priced game,” Okajima says. “A lot of people already had their expectations set at 2,000 yen ... so how could we justify the higher pricing with the same game?” The producer felt the best moment would be Earth Defense Force 2017’s jump to HD. “That was the only reason we could ask for higher pricing to most of the fans. and I think people were mostly OK with that.”

“We intentionally separated Insect Armageddon in Japan and everyone thought it was a completely different game.”

With Earth Defense Force 2017 selling more in the West than back home, D3P attempted to capitalize on the situation. At that time the publisher had a North American sister company called D3PA, which owned the studio Vicious Cycle, and Okajima started talks about a new take on Earth Defense Force. “Vicious Cycle really liked the franchise to start with, and they told me that they wanted to create the first Western version of Earth Defense Force. I really liked the idea because I wanted to see how Americans would create Earth Defense Force with their resources and crew, so I approved it.”

Sandlot’s developers don’t appear to have been jilted by the situation, though Okajima admits that he was nervous when he had to break the news. “We actually wanted to see how other people would develop this game, so I was curious how it would turn out,” says Noguchi.

Around the same time, Sandlot was developing a Wii-exclusive project for Nintendo called Zangeki no Reginleiv, a motion-controlled action game based on Norse mythology but with notable similarities to Earth Defense Force. “There’s a very strong core game design to Earth Defense Force, with a list of bullet points that we can’t miss even one of,” Noguchi says. “So using that core framework, we thought about how we could come up with a new game for a different client using swords, not guns. We applied what we learned to this game for Nintendo.” The game was fairly well received, but didn’t sell particularly well and never made it out of Japan.

Over in North Carolina, Vicious Cycle was working on what would become Earth Defense Force: Insect Armageddon, which came out for the Xbox 360 and PlayStation 3 in 2011, with a first PC release for the series later in the year. The response from fans was mixed.

“Honestly, it wasn’t the best game,” Okajima says. “But it was fine. I didn’t think there was enough content.”

In Japan, Insect Armageddon wasn’t even considered an Earth Defense Force game — or rather, it wasn’t considered a Chikyuu Boeigun game, because the name was a phonetic Japanese transliteration of the English title. “We intentionally separated Insect Armageddon in Japan and everyone thought it was a completely different game,” Okajima says. “A lot of people posted complaints saying it was very short, but it wasn’t like ‘this isn’t Chikyuu Boeigun!’ or anything like that, so it was OK.”

Sandlot returned to the series in 2013 with Chikyuu Boeigun 4, which was released in the West as Earth Defense Force 2025 the following year. Around this point, Sony allowed the series back on its platform, and an expanded PlayStation 4 version called Earth Defense Force 4.1: The Shadow of New Despair followed in 2015.

The most recent game in the series is Earth Defense Force 5 for the PS4, which came out last December in the West and a year earlier in Japan. It’s the first Earth Defense Force game to have been built exclusively for current-generation hardware, and you’ll occasionally see the odd flashy lighting effect to set it apart from previous titles, but the overall presentation is similar to how it’s always been. The graphics are rudimentary, the framerate is unstable, but hell if there isn’t a lot happening on the screen.

“We always try to push the hardware to capacity, just so that we can give the player the best experience with more enemies and so on,” Noguchi says. “Of course sometimes we get a bunch of feedback from first-party that this isn’t ideal — the framerate is too slow, or there are other technical issues, so we have to deal with that. But we don’t set the bar low; we set it pretty high. We try to add more and go beyond what people expect.”

“From my perspective, if I asked the player if they want a very stable and conservative gameplay experience, or something extraordinary with some technical issues, which game would they prefer?” asks Homma. “I think the latter is more appealing.”

Nevertheless, Sandlot does imagine a future in which console hardware is able to keep up with its visions for ant-induced apocalypse. “One thing I want to clear up is that pushing the hardware is not the ultimate goal — we want to make the experience better and better for every EDF game,” says Noguchi. “If somebody tells me that showing 200 ants on the battlefield is better than showing 100, we have to try hard to show 200 ants. That’ll probably end up pushing the hardware pretty hard. But I personally think that showing 200 ants probably makes no difference, and if it’s unnecessary then we won’t have to push the hardware, which means we’ll probably have more stable Earth Defense Force games in the future on better platforms.”

Courting North American players, again

Earth Defense Force has come a long way — the last game sold for about four times as much as the early Simple Series titles, which brings us to this week’s launch of what appears to be the most polished game in the franchise yet. With a darker tone and a San Francisco setting, Earth Defense Force: Iron Rain is another explicit attempt to target the Western market. Unlike Insect Armageddon, however, it’s being handled by a Japanese developer, and Okajima is confident that things will work out better this time.

“For Insect Armageddon, the initial business vision of creating an Earth Defense Force game targeting a Western audience was a great idea, and for Iron Rain I still have the same vision — this is my second attempt,” the producer says. “What’s different is that because I don’t speak English, I sometimes don’t understand the working processes of Western companies, so this time I picked a company in Japan so that I have more control over the creative process and game design — but again, targeting an international audience. If I asked Sandlot to create an international version of Earth Defense Force I’d be afraid that we’d lose everything, so instead I prefer going outside of Sandlot to look for someone who can create a completely different version.”

D3P tapped Yuke’s, best known for its long history developing WWE games for THQ and now 2K Sports, because of its experience with the Western market. Sandlot isn’t advising on Iron Rain’s development, but Okajima says the new team has a lot of respect for the people behind the original series. “Not only because Sandlot is [made up of] the original creators but also they’re legends — they have way more experience. The people at Yuke’s are a lot younger so they respect Sandlot. I heard from the younger creators at Yuke’s that the more they worked on this game, the more they understood why Sandlot is great.”

“The ultimate goal for this project is to deliver Earth Defense Force gameplay to the Western audience. We really wanted to keep the original game concept from Sandlot,” says Naoto Ueno, senior creative director at Yuke’s’ Yokohama studio. (The company is based in Osaka, but sent several developers to Yokohama to work on Iron Rain.) “We also wanted to add realism to this Earth Defense Force. For instance, when you see a Hollywood superhero movie, you can see the source of the power and the details of the suit and so on. We took that idea and applied it to this Earth Defense Force to make the action more believable.”

How Iron Rain is received by series veterans and newcomers alike remains to be seen, though Okajima says he’d like Yuke’s to continue developing Western-focused Earth Defense Force games on a parallel track. Sandlot, too, also expects to make further games in the original series.

“A lot of people and fans internationally ask the same question of why Earth Defense Force is good,” Noguchi says. “But we know why — we have a formula and science for that, and it’s something we believe we can stick with to keep developing console games. We think Earth Defense Force 5 is a pretty good game, and we are confident that we can create the future Earth Defense Force for whatever platforms come next using our magic.”