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

• Auto-Fire For Player 1
  ENSTPVSN
• Auto-Fire For Player 2
  EYNVINSN
• Hand Weapons Last 4 Times Longer
  AEKVXLII
• Only 1 Hand Weapon
  ZAOVEPAA
• Infinite Hand Weapons On Pick-Up For Players 1 And 2
  ENVVKLEI
• Infinite Hand Weapons And Firearms On Pick-Up For Players 1 And 2
  OXVVVLVS
• Enemies Don’t Fire Handguns
  XVKZVEXK
• Become Invisible And Invincible
  XTOVVEXK
• P1 & P2 Infinite Energy For Heavy Barrel
  XTXUUTW
  Note: Once Heavy Barrel is assembled, it has infinite energy.