Here are some cheats and tips for the game Mr. Do.
Level select:
Press Down(8) when the Universal logo is displayed
during the introduction sequence. A level select option will appear
on the main menu.
Ninety nine lives:
Press Left(8) when the Universal logo is displayed
during the introduction sequence.
Alternate title screen:
Press Up(8) when the Universal logo is displayed
during the introduction sequence. “Mr. Du!” will appear
on the title screen.