The following are known Game Genie Codes for Gradius on Nintendo Entertainment System (NES).

• Both Players Have Infinite Lives
  SXOOYYVI
• Both Players Start With 1 Life
  AENELZLA
• Both Players Start With 6 Lives
  IENELZLA
• Both Players Start With 9 Lives
  AENELZLE
• Keep Power Capsules
  KOXOLYSP
• Increase Force Field Protection
  NNOEKPIE
• Never Lose Weapons
  YGUONUZS
  YGKPUUIL
• Automatic Fire Is On For Normal Gun
  NLLXZP
• Your Ship Is At The Very Top Of The Screen
  YAAKIO
• Enemies Farther Ahead
  KPPZZL
• No Enemies Except End Guys
  NYPZZL
• Invincibility
  GKOKPPSX
  NEOKZOLP
  XKOKLOOG