Tetris Jr.

One rotation direction. There are clockwise and counterclockwise versions; one rotates only clockwise, other only counterclockwise.

Gimmicks
The manual of Tetris Jr. describes eight modes.

Game 1 and Game 5
Special blinking pieces are present, similar to some of the blocks from DuelTris. They can add or remove blocks until they lock.
 * I tromino, vertically oriented: Press rotate to drop a single block below the piece.
 * Domino, vertically oriented: Press rotate to remove a single block below the piece.
 * Single block: Press rotate to drop a single block below the piece. This piece also has deep drop, meaning it passes through layers of blocks to fill gaps.

Game 2 and Game 6
Playfield starts with garbage. Each round ends when a line is cleared in the bottom row, as in The Next Tetris.

Game 3 and Game 7
Blinking tetrominoes break into individual blocks when they lock, much like the Multiminos of The Next Tetris.

Game 4 and Game 8
Blinking tetrominoes break into individual blocks of antimatter, which remove blocks from the field, when they lock. For example, an L tetromino placed on its side of length 2 will remove three blocks from one column and one from the next.

Games 5-8
Every 60 seconds, a garbage line is added.

Scoring
Scoring is similar to the system LJ65 used before switching to combo-based scoring.
 * Single: 100
 * Double: 300
 * Triple: 700
 * Tetris: 1500
 * Level up: 400