All Working Pokemon Puzzle League Cheats - Nintendo 64

Master code
Hold [Z] and press [A], [B], [R], [A]x2, [B], [R], [A] at the title screen. All selections in the Puzzle University will be unlocked.

V-Hard difficulty setting
Hold [Z] and press [L]x2, [A], and [B] at the difficulty selection screen. Alternately, successfully complete the game under the Hard difficulty setting.

Mewtwo level
Hold [Z] and press [B], [Up], [L], [B], [A], [Start], [A], [Up], [R] at the trainer selection screen. Alternately, successfully complete the game under the S-Hard difficulty setting.

Secret characters
Hold [Z] on controller one and simultaneously press [L] + [R] on controllers one and two at the two player trainer selection screen. Alternately, successfully complete Spa Service.

Continue without continues (1P Stadium)
When you lose and the game asks if you want to retry, select "No". After that, return to the 1P Stadium. Select your name and continue playing. When you see your records, it will be as if you never lost.

Alternately, if you know you are not going to catch up or win, just press [Start] before you lose and choose "Return to Select".