Short answers, pulled from the story.
Tetsujin 28-go is a manga series written and illustrated by Mitsuteru Yokoyama, first serialized in Kobunsha's Shonen magazine from July 1956 to May 1966. It follows ten-year-old Shotaro Kaneda, who controls a giant robot built by his late father as a wartime weapon for the Imperial Japanese Army.
The name "Tetsujin 28" translates literally as "Iron Man No. 28," but the Marvel Comics character Iron Man had already established that name in the American market. The English dub, handled by Fred Ladd, renamed the series Gigantor, changed all character names, removed the wartime setting, and dubbed only 52 of the original 97 episodes.
Yokoyama drew from three sources: his personal experience watching Kobe be bombed flat by B-29s during World War II, the concept of the Vergeltungswaffen (Nazi wonder weapons developed as a last resort), and the 1931 film Frankenstein, which shaped his belief that the robot itself is neither good nor evil.
Katsuhiro Otomo borrowed the name Shotaro for Akira's protagonist, Shikishima for the colonel, and Tetsuo from Shikishima's son in the original Tetsujin series. In the Akira Club book, Otomo stated that Akira could be said to be based on Tetsujin 28-go, and the character Akira is referred to as "No. 28" by the scientists experimenting on him.
Tetsujin 28-go is credited as the first work to feature a humanoid giant robot controlled externally via remote control by a human operator. When its 1963 anime adaptation aired on Fuji TV, it was among the first Japanese anime to feature a giant robot at all, preceding the Mazinger Z series that followed in 1972.
The Imagi Animation Studios film was cancelled. A computer-animated teaser featuring Tetsujin and Black Ox was revealed on the 26th of December 2008, and a full teaser launched on the 9th of January 2009, but Imagi went defunct in 2010 and the project was scrapped along with several others.