Astro Boy: Omega Factor is one of the highlights of the GBA catalogue and arguably shows Sega's Hitmaker studio (which collaborated with Treasure on the game) at its finest.
However, working on the game came at a considerable cost for artist and designer Tomoharu Saito, who, it has been revealed, lost a leg during its production.
"Because of this work, he was delayed in going to the hospital, lost one of his legs, and finally died," reveals Tetsu 'Tez' Okano, who also worked on Astro Boy and is famous for leading development on the Dreamcast RPG Segagaga.
"This game is filled with his soul. Tomoharu Saito and I were similar. He was known for Gourmet Warriors and I was known for SEGAGAGA, but we weren't considered proper creators. That's why we poured all our heart and soul into Treasure and Astro Boy and created it."
Okano adds that he's "not saying Astro Boy is a good game because it sacrifices someone's lifespan. I just wanted people to know about the work of Tomoharu Saito, who is not well-known to the world. The reason he worked so hard to hide his illness was simply for his own self-respect as an artist."
Saito was never a full-time employee of Sega, according to Okano. Indeed, this page suggests he freelanced for companies like Sega, Masaya and Cave, although he did accept a full-time role at Square between the years of 1998 and 2000 before returning to the world of freelancing.
During his career, Saito contributed to games such as Streets of Rage 2, Gourmet Warriors, Front Mission: Gun Hazard, Gunstar Super Heroes, Culdcept and Bleach: The Blade of Fate.
Saito died in 2006, at the age of 38. The cause of death was the cancer synovial sarcoma, which was the reason he lost one of his legs during his work on Astro Boy. According to Game Developer, Saito later said that "legs aren't necessary in the illustration industry," but the cancer eventually spread to his lungs.