With millions of copies sold, Level-5's Professor Layton franchise is an unquestionable hit. Already, the property has spawned one feature-length film, and is expanding to its fifth game in Japan. (The Unwound Future, which was released two weeks ago in America, is the third game in the series.) Who could have predicted the runaway success of the series? Not even Level-5's president, Akihiro Hino, could have seen it coming.

In an exclusive interview, Hino told us that "I obviously didn't imagine the series would achieve the success it has." But, he attributes the franchise's achievements to Level-5's goal to "make an adventure game that anyone could play." Given the popularity of the games, Hino finds it unsurprising that a number of copycats have since followed, such as Puzzle Agent and Blue Toad Murder Files. "Doesn't it follow that if a game gets popular enough, similar games will start to appear?," he asked us.

Nintendo eventually picked up the publishing rights for a North American release, which posed a number of challenges for the localization team. Hino admits that the first game was developed "without much consideration" for international audiences. As such, "we have had to alter and even remove certain puzzles," Hino explained to us. "The reason is usually due to their use of Japanese, or because a puzzle or joke would work in some regions but not in others. Ways of thinking, language, culture, and even religion differ from region to region, so we remove puzzles we feel wouldn't work, and try to replace them with puzzles that players from that market will enjoy."

After the trials of developing the first game, Level-5 then embraced a more international design for subsequent games. "With the second game, and especially with The Unwound Future, we've cut down the number of puzzles requiring removal by not including as many language- or culture-specific puzzles to begin with." With the opening of a US office, Hino explains that future games will be even more tailored for American audiences. "By establishing an office outside of Japan, we'll be better able to cater to the opinions and trends of our overseas audiences. We're hoping this increased understanding of what American gamers want will help us make Professor Layton games that are even more suited to American tastes."

Unfortunately, the opening of a US office hasn't facilitated plans for an American release of the film. "We don't have any plans to release the movies in America currently, but we'll make sure to let you know if that changes."

While US fans may not be able to enjoy the movie, the franchise promises to expand its ambition for its upcoming "second season." Hino explains that in the Layton series, "story is absolutely crucial. It's as if the story is responsible for linking all the puzzle-solving bits together. We've certainly tried to make each of the titles enjoyable in their own right, but there are also elements connecting all three games that I think people who play the entire series will particularly enjoy discovering." Unwound Future represents the end of the first season of Layton games. "But the games in the second season will feature even stronger over-arching story details," Hino teased.

Part of the second season will be The Mask of Miracle, the series' first foray on the Nintendo 3DS. "We were originally developing it as a Nintendo DS title, but decided to switch gears and develop it as a Nintendo 3DS title instead," Hino explained. "The game has really undergone some major changes as we've come to understand the capabilities of the Nintendo 3DS." Unfortunately, Hino wouldn't reveal much more about what we can expect from the 3DS sequel. He did offer this mysterious tease, though. "Even Professor Layton's appearance is changing quite a bit, but you'll have to wait and see what I mean!"

This article was originally published on Joystiq.