An Xbox exclusive update for Cuphead is now available to celebrate the game's sixth birthday.

The update includes a new Bonus menu of artwork, music, and behind-the-scenes videos, showing never-before-seen concepts and unused art as well as the entire Cuphead soundtrack.

"Original sketches, concept art, process footage of painting or model work, unused music tracks, orchestra session footage, you name it," Studio MDHR co-director Chad Moldenhauer told Xbox Wire discussing the additions.

"Knowing that we wanted to give our thanks to the Xbox community that has shown us love from day 1, we really thought about the kinds of things we would want to see as fans of Cuphead. The goal was to make this update feel like a real peek behind the scenes at what went into bringing the game to life, across all parts of development."

Moldenhauer continued: "With our process being so painstaking once we put pencil to paper, we often use paint tools during brainstorming sessions to communicate ideas very quickly to one another for the broad strokes of a boss attack or phase transition.

"A few of these made their way into the photo gallery, and we think they're a fun break from tradition for the more handcrafted art we usually put out."

Cuphead was first announced in 2013, the same year the ID@Xbox indie game programme began. The game was eventually released in 2017 on Xbox and PC, before reaching Switch in 2019 and PlayStation in 2020.

"It's not a stretch to say that without the ID@Xbox program, Cuphead would not be the game it is, or have become the success it has," said Studio MDHR studio director Maja Moldenhauer.

"It's no exaggeration to say that we couldn't possibly have envisioned Cuphead reaching as many people as it has since it launched on Xbox six years ago.

"Like so many developers releasing their first game, our dream goal was to connect with a large enough audience that we could stay together as a team and work on another project. We ended up - and remain - blown away by the audience we found for our little animated adventure. And it all started with the love and enthusiasm we received from fans on Xbox."

"A brutal game that's equal parts frustrating and exhilarating, delivered in the mesmerising style of a prohibition-era cartoon," reads our Eurogamer Cuphead review from its original launch.

It was followed by the Delicious Last Course DLC last year: "More of the sumptuous visuals and wonderful jazz score. More of the high difficulty, with bosses taunting you every time you lose. More of that succulent satisfaction when you finally hit the knockout."