According to Official Guinness Records,
The highest score on Nemesis (Konami, 1985) is 1,196,400, achieved by Joe Martin (USA) and verified by Twin Galaxies on 28 January 2010.
Featured in Guinness World Records Gamers Edition 2011Nemesis is a lesser-known version of Gradius (Konami, 1985).
For a complete list of 2010 records, please visit 2010 Guinness Records in United States.