The password for low gravity is "mp_gravity #" (Type any number in place of the # sign).
The default gravity is 800. If you want to jump higher then type any number below 800 or if you want no one to jump type any number above 800.
Password - 1961 1966-12-16 was released on: USA: 16 December 1966
Password - 1961 - 1966-12-16 was released on: USA: 16 December 1966
Password Plus - 1979 1982-02-16 was released on: USA: 16 February 1982
Super Password - 1984 1985-12-16 was released on: USA: 16 December 1985
Super Password - 1984 1986-04-16 was released on: USA: 16 April 1986
Super Password - 1984 1986-06-16 was released on: USA: 16 June 1986
Super Password - 1984 1986-07-16 was released on: USA: 16 July 1986
Super Password - 1984 1986-10-16 was released on: USA: 16 October 1986
Super Password - 1984 1986-01-16 was released on: USA: 16 January 1986
Super Password - 1984 1988-05-16 was released on: USA: 16 May 1988
Super Password - 1984 1988-08-16 was released on: USA: 16 August 1988
Super Password - 1984 1988-11-16 was released on: USA: 16 November 1988