was released on the Sinclair Spectrum, Commodore 64 and several other computer systems in the 1970's.
I don't think the Sinclair Spectrum and Commodore 64 even existed in the 1970s! I guess it should be "1980s". Unless it was released on other computer systems in the 1970s? --Eriorg 06:59, 30 July 2006 (EST)