The following are known Game Genie Codes for Mercs on SEGA Genesis.

• CTBT-AA4A
  Master code, must be entered
• ALAT-AA4N
  Almost Infinite life
• RHNA-A6Z0
  Infinite mega crash bombs
• ATMT-AAAA
  Start with 4 mega crash bombs
• AYMT-AAAA
  Start with 5 mega crash bombs
• A2MT-AAAA
  Start with 6 mega crash bombs
• A6MT-AAAA
  Start with 7 mega crash bombs
• BAMT-AAAA
  Start with 8 mega crash bombs
• A5KA-AA4W
  Infinite continues
• ETMT-AACA
  Start with 8 continues in arcade mode, normal
• EAMT-AACA
  Start with 7 continues in arcade mode, normal
• DTMT-AACA
  Start with 6 continues in arcade mode, normal
• DAMT-AACA
  Start with 5 continues in arcade mode, normal
• ETMT-AACC
  Start with 8 continues in arcade mode, hard
• EAMT-AACC
  Start with 7 continues in arcade mode, hard
• DTMT-AACC
  Start with 6 continues in arcade mode, hard
• DAMT-AACC
  Start with 5 continues in arcade mode, hard
• ETMT-AAB8
  Start with 8 continues in arcade mode, easy
• EAMT-AAB8
  Start with 7 continues in arcade mode, easy
• DTMT-AAB8
  Start with 6 continues in arcade mode, easy
• DAMT-AAB8
  Start with 5 continues in arcade mode, easy
• RG3A-A61C + B83A-BJ9A
  Start with 5x normal firepower level
• RG3A-A61C + D83A-BJ9A
  Start with 10x normal firepower level
• RG3A-A61C + JC3A-BJ9A
  Start with 20x normal firepower level
• RG3A-A61C + 7C3A-BJ9A
  Start with 40x normal firepower level