Here are some cheats and tips for the game Tetris (Tengen).
Force 1 x 4 piece:
Pause game play and press Up(2), Down(2), Left,
Right, Left, Right, B, A, Start.
The piece currently falling will transform into a 1 x 4 piece.
Note: This may only be done once per level.
Level select:
Press Start to pause game play, then press Up,
Down, Up, Down, Left, Right,
B(2), A.