Ex-Bungie audio director Marty O'Donnell.

Bungie has reassured fans that upcoming shooter Destiny remains on track after the exit of veteran composer Marty O'Donnell.

Last night O'Donnell announced he had left Bungie, claiming on Twitter he had been "terminated without cause".

The news sparked concern among the Bungie community. O'Donnell, creator of the iconic soundtrack to the Halo series, was much-loved by fans, and many were looking forward to enjoying his work on Destiny, due out this September on PlayStation 4, PlayStation 3, Xbox One and Xbox 360.

Speaking to Eurogamer in an interview at Bungie's Bellevue, Washington headquarters yesterday, chief operating officer Pete Parsons said Destiny was "close to shipping", and O'Donnell's music remained in the game.

"I think the Bungie fanbase is going to look forward to hearing Marty's music, Mike Salvatori's music, C. Paul's music and Paul McCartney's music in the game," Parsons said. "That's going to be exciting for people. It's going to be a great, fantastic experience."

As Bungie audio director O'Donnell worked with long-term collaborator Mike Salvatori on Destiny's music, as well as in-house sound designer and composer C. Paul Johnson. Musician Paul McCartney collaborated with O'Donnell on the game's soundtrack.

While Parsons was unable to go into the reasons for O'Donnell's departure, he denied it would impact negatively on Destiny, adding much of the game had already been completed.

"I believe people will be transported not just by the activities and the stories within the Destiny universe but by the sights and the wonderful sounds and music," he said. "We have a fantastic team. We're pretty close to shipping. There's a lot of polish left to do, lots of tweaking and tuning, but a lot is already complete."

Despite Parson's comments on the matter, questions remain. After O'Donnell's late night tweet hit the headlines, Bungie community manager David Dague paid tribute to the composer in a blog post titled, "There are those who said this day would never come."

"For more than a decade, Marty O'Donnell filled our worlds with unforgettable sounds and soundtracks, and left an indelible mark on our fans," read the brief statement. "Today, as friends, we say goodbye. We know that wherever his journey takes him, he will always have a bright and hopeful future.

"We wish him luck in all his future endeavors."

Bungie's claim that the two parties went their separate ways "as friends" seems in conflict with the wording of O'Donnell's tweet, in which he said he was "saddened" that he had been "terminated without cause".

And the timing of O'Donnell's tweet has raised eyebrows. He left Bungie on 11th April but waited until the 15th to make the announcement - amid a media event at Bungie's office where interviews with key staff were set to take place.

Destiny is designed as a decade long franchise that should see a number of games launch as part of a high-profile publishing deal with Activision. How Bungie handles the music for future Destiny titles will be of keen interest to fans.