The following are known Game Genie Codes for Killer Instinct on Nintendo Game Boy.

• 002-199-19E
  Infinite time
• 103-1CD-80C
  Round starts with 10 seconds
• 303-1CD-80C
  Round starts with 30 seconds
• 503-1CD-80C
  Round starts with 50 seconds
• 753-1CD-80C
  Round starts with 75 seconds
• FA7-B0B-4C1
  Infinite energy
• 012-EAD-919
  Strart with very little energy
• 4B2-EAD-919
  Strart with 25% energy
• 882-EAD-919
  Strart with 50% energy
• B42-EAD-919
  Strart with 75% energy
• 00B-428-6E2
  Fierce Tiger Fury does no damage
• 88B-428-6E2
  Fierce Tiger Fury does more damage
• FFB-428-6E2
  Fierce Tiger Fury kills
• 00B-698-916
  Fierce Wind Kick does no damage
• 88B-698-916
  Fierce Wind Kick does more damage
• FFB-698-916
  Fierce Wind Kick kills
• 00B-838-91E
  Fierce Laser Blade does no damage
• 88B-838-91E
  Fierce Laser Blade does more damage
• FFB-838-91E
  Fierce Laser Blade kills