From the title screen, press
⇧ / ⇩ to select an option, then press to confirm your selection. 

Select PRESS START to begin the game from the beginning.
Anytime a Robot Master stage is cleared, a password is displayed in the form of a grid with chips on it. You can then select PASS WORD on the title screen to enter a password and begin from this same point.

Select a space on the grid with , and press to place a chip. A placed chip can be removed by highlighting it and pressing .

Place the cursor on END with and press to confirm the password.

Note: Once you enter the password screen, you cannot go back to the title screen and must either input a correct password or reset the game.