This is a revision of Cyberpunk 2013 with a majority of the rules staying the same. The one major revision, was the removal of the 'opposed' roll. Under the 2020 combat system a d10 was used to resolve your attack which was modified both by your skills and by some skills of your opponent, plus other combat conditions.
Skill checks were also resolved using a d 10.
There may have been some slight over lap with a few of the supplements at the tail end of 2013, but the rule similarities made them 'useable' until new supplements were made for the 2020 system.
There were two versions of the Cyberpunk 2020 rule book printed; 1st and 2nd printing. The 2nd printing had some rules claification notes (and some new artwork) printed in it. The original text was not altered.