AlphaDream, the 28-year-old Japanese studio best known for developing the Mario & Luigi RPG series, is seeking bankruptcy protection.

The company filed bankruptcy papers in Japan on Tuesday, Gematsu reported. A translated Yahoo! News story from Japan said the studio was crippled by high development costs and sluggish sales performances for the works AlphaDream had completed. The story said the studio listed debt of 465 million yen (roughly $4.3 million) as of March 2018.

AlphaDream’s work on the Mario & Luigi RPG series began with Mario & Luigi: Superstar Saga for the Game Boy Advance in 2003. The studio went on to make four more RPGs, the latest being Mario & Luigi: Paper Jam for Nintendo 3DS in 2016. It delivered two 3DS remakes of older RPG titles since then: Bowser’s Inside Story and Superstar Saga.

AlphaDream was also behind two adaptations of the Hamtaro anime — 2004’s Hamtaro: Ham-Ham Games and 2008’s Hi! Hamtaro Ham-Ham Challenge, for the Nintendo DS.