Rally-X was released in January 1981 in North America by Bally/Midway under license from Namco.
In the introduction to the bonus stages, the Namco version misspelled 'Challenging' as 'Charanging'. This was corrected in this export version.
In 1981, "Defender
", and "Battlezone
" were shown alongside Rally-X at a trade show sponsored by the Amusement Machine Operators of America. It was believed that Rally-X would be the top money-earner. Defender went on to sell more than 60,000 units - more than disproving these projections - and cemented its place in video game history.
A Midway Rally-X unit appears in the 1982 movie 'Tron'.