In the mid-’90s Nintendo entered into an unlikely partnership. The company known for Super Mario Bros. and The Legend of Zelda teamed up with Squaresoft (now Square Enix), the developer behind the Final Fantasy series of dense role-playing games. The goal was simple: to extract the gameplay and structure of an RPG like Final Fantasy, and inject it into the light hearted universe of Mario. It worked! Super Mario RPG not only became a cult hit following its release 1996, but spawned two different Mario-themed role-playing series, with Paper Mario and Mario & Luigi.

Like their predecessor, the two series have been critical and cult hits over the years, combining lighthearted humor with a familiar setting and a handful of inventive twists to the role-playing genre. None has proven to be a huge financial success — Mario is still better known for his platforming and kart racing adventures. Nonetheless, Nintendo hopes to introduce the series to a wider audience with Mario & Luigi: Paper Jam, which recently launched on the Nintendo 3DS and brings the two series of Mario RPGs together within one game.

"Both titles were games in which the gameplay followed the storyline in an adventure or role-playing game format, so we thought they would combine well," says director Shunsuke Kobayashi, from developer Alphadream. "In addition, both series incorporated various jokes along the way to entertain the player, and we thought that it would be okay to mix them together."

Paper Mario branched out from the original Super Mario RPG by introducing an entirely new papercraft world to explore. Developed by Intelligent Systems — the studio behind strategy games like Fire Emblem and Advance Wars — the games featured 2D paper characters moving through a 3D world, leading to all kinds of creative opportunities for puzzle-solving (and jokes). The series debuted with the release of the original Paper Mario on the Nintendo 64 in 2000.

Mario & Luigi went in a different direction. Alphadream has been the sole developer behind the series since its debut on the Game Boy Advance in 2003, and it’s a franchise defined by the relationship between the titular brothers. You control both Mario and Luigi at the same time, using separate buttons to handle their jumping. The two can also work together in battle, using perfectly timed attacks to inflict more damage. The games blended the familiar platforming of Mario with the turn-based structure and story-driven quest of an RPG to create an experience that felt distinct and playful.

The original goal of Paper Jam wasn’t necessarily to merge these two series, but simply to introduce a new playable character into the Mario & Luigi formula. "We originally started this project based on the idea that, while we used to play Mario & Luigi games with two buttons, could we deviate from that formula and create a game using three buttons?" explains Akira Otani, producer on the game at Nintendo. "We were first thinking about various characters such as Bowser, but then thought, ‘wouldn't it be interesting to have Mario work with another Mario character?’"

The challenge, though, was to not overcomplicate things. One of the most important aspects of both Paper Mario and Mario & Luigi is that they’re much more accessible than most RPGs. In a genre full of huge, complex, intimidating games, Mario’s RPG adventures are something you can play and enjoy even if you don’t know the difference between a dragoon and a dragon. When the team first introduced the third playable character, Paper Mario, they created a system that forced players to tap three buttons in quick succession in order to dash (an important feature in the final game). "We thought that was challenging, but when we showed it to [Mario and Zelda creator Shigeru] Miyamoto his opinion was, ‘No good, that's too hard. Make it more simple!’" says Otani. "Since this is a Mario game, it has to be something accessible to any audience." The final version simply has you holding a button after all three characters jump.

Aside from gameplay, Paper Jam also manages to blend together the two series’ unique humor relatively seamlessly. Mario & Luigi jokes are usually at Luigi’s expense, while Paper Mario pokes fun at its paper-thin characters with visual gags and a lot of puns. Paper Jam has the best of both worlds, while also adding a twist of its own. The best moments have the 3D and paper versions of the same character interacting with each other. In one memorable scene both versions of Princess Peach are trapped in a cage; while the 3D princess worries about being rescued, her paper counterpart silently slips through the bars.

Paper Jam is the 10th Mario RPG to be released since 1996; what was once just a weird curiosity has gone on to become an enduring franchise. And it’s one that is unlikely to end anytime soon. "We think that maybe the Mario world is a deep world," Otani says, "or maybe a world that players would not get tired of revisiting."