Donkey Kong Land
Collect the letters "K", "O", "N",
and "G" all one the same level, then complete the level.
The game is also saved after beating a Boss.
Enter the bonus stage just half-way through level 8 (Gangplank
Galleon). Collect the extra life and leave the stage. Re-enter
the stage to collect another extra life. Repeat this procedure
to collect an unlimited amount of lives.
Walk on hands:
Stand still, then hold Down
and press A. Press A while walking on your hands
to perform a super jump.
Although posted as a valid code
on other web sites, it does not function in the retail version
of the game.