Continue game play:
After losing all lives, hold A + B and press Start on the title screen. Alternatively, hold A and press Start at the title screen.

Swing sword:
Press A + B and any direction on the D-pad.

Special bonus level:
Walk around the screen in a counter-clockwise circle and touch each corner. Blue hearts are worth 100,000 points during the special bonus level.

10 million points:
Intentionally die in levels 1-3, 2-2, 3-2, 3-4, 4-1, 5-1 and not in any other level.