The following are known Game Genie Codes for Mr. Do! on Nintendo Game Boy.

• 015-B2E-E66
  Start with 1 life
• 065-B2E-E66
  Start with 6 lives
• 095-B2E-E66
  Start with 9 lives
• FA7-28C-4C1
  Infinite lives
• 3E8-2CE-191 + 098-2DE-C42 + 188-2EE-6EA
  Keep 1 map layout thru the game. (You still will progress from map to map, but the layout stays the same.)
• 235-6AC-6E2 + 214-78D-4C1
  Start new game from level you last died on