The following are known Game Genie Codes for Lethal Weapon on Nintendo Game Boy.

• 1E9-CEE-E6B
  Start with 50% weapon energy
• FA6-01E-4C1
  Infinite weapon energy
• 239-C3E-E6B
  Start with 50% life energy
• FAA-1DD-4C1 + FAA-A5D-4C1
  Infinite life energy, except when you fall down holes.
• 004-5BB-195
  No enemies (This code can be switched on/off)