Tetris (NES, Tengen)
Tengen's Tetris is basically an improved revision of the Vs. System arcade game, which itself was a port of Atari's own arcade game. It was pulled from shelves after a mere month due to complicated licensing disputes with Nintendo. It had a few features Nintendo's own version (released six months later) did not have, and because of that some consider it the better Tetris game of the two.
A rendition of the "level complete" theme used in Atari's arcade version.
The game features some leftover sound effects from the Vs. System version, all of which are unused.
Pause the game and press Up, Down, Up, Down, Left, Right, B, B. Pressing A increases your level, allowing you to go beyond the usual 9 levels, up to Level 17.
Free I Tetrimino
Pause the game and press Down, Down, Left, Right, Left, Right, B, A to get a free long-piece tetrimino. This can be done once per level.