The New Tetris

The New Tetris for N64 was developed by H2O and published by Nintendo. Like Tetrisphere before it, The New Tetris features a soundtrack by Neil Voss.

It has lock delay, soft and firm drop, 4&times;4 squares, hold piece (though not IHS), three next pieces, ghost piece (TLS), and mild wallkick (notably, certain configuration of L/J-spin triple works but lock delay is still abusable on no-garbage play). The speed never gets anywhere near 20G. The colors of some tetrominoes differ from those of the current Tetris Guideline: L is magenta, T is yellow, and O is light gray.

Top-out condition is the same as in Atari's Tet&#1103;is and the "push" mode of Nintendo's Tetris DS: the game ends when one block is placed above the playfield's top row.

The New Tetris defines twists (known in the manual as "spin moves") differently from the "T-spin" rule used in Tetris Worlds, Tetris DS, and other games that use SRS. In this game, a twist occurs when a tetromino locks in a position such that it cannot move left, right, or up without rotating.

Tetromino behavior

 * ARE: ca. 500 ms
 * Randomizer: Preliminary data suggests a 63-piece bag (nine bags)
 * Entry position: rows 21-22, centered, JLSTZ rounded to the right
 * Lock delay: ca. 500 ms, step reset, no manual lock
 * DAS: ca. 10 frames, repeating 5 frames
 * Up: Firm drop, not locking
 * Down: Drop, not locking
 * Top out: tetromino locks with a block in row 21

The rotation system of The New Tetris is a predecessor to SRS, with somewhat flexible wall kicks and floor kicks. But surprisingly for a game co-developed by BPS, its handling of J, L, S, and Z in free space is more like Atari Games' arcade game and its unlicensed NES port than like BPS's previous games.

The wallkicks are following:

Squares
A 4x4 block square made out of four tetrominoes becomes a monolithic square of the same size.
 * A square is entirely within the playfield.
 * If things are projecting out of a 4x4 block region, it is not a square.
 * If it has a hole in it, it is not a square.
 * If it contains blocks that form part of a tetromino or square that was partially removed, it is not a square.


 * Monosquare
 * A 4x4 block square made out of four identical tetrominoes.


 * Multisquare
 * Any other 4x4 block square made out of four tetrominoes.

Details
If a tetromino forms two overlapping squares at once, the gold wins over silver, the top wins over the bottom, and the left wins over the right. It is not known whether top wins over the left.

The following diagrams use The New Tetris colors, which are not the same as the later Tetris Guideline colors:

Given that The New Tetris is proprietary software, the public does not know exactly how the detection is implemented in the game program. But given the definition of a square above, it is straightforward to transform this definition into an algorithm for recognizing squares that behaves identically to the game's algorithm:

The playfield is stored as a matrix of 10 columns by 20 rows. Each entry has 4 bits for color, 1 bit for right connection, 1 bit for down connection, 1 bit for left connection, 1 bit for up connection, and 1 bit for being part of a tetromino that was broken by a line clear.

Before and after checking for lines, the engine scans the playfield top to bottom, left to right, looking for monosquares and marking them as gold. Then it makes a second pass, looking for multisquares and marking them as silver. To see if there is a square in the 4x4 cell region whose lower left corner is column x of row y:
 * 1) Make sure that the left edge isn't connected to anything. That is, make sure that the blocks at (x, y), (x, y + 1), (x, y + 2), and (x, y + 3) don't have their left connection bit set to true. Do the same for the other four edges.
 * 2) Make sure that all cells in the region are filled with blocks.
 * 3) Make sure that all blocks in the region belong to whole tetrominoes (not tetrominoes with a block broken off, and not pieces of squares that have already been marked).
 * 4) In the first pass, make sure that all blocks in the region are the same color.

Side note: The author of The New Tetris claims that the game used a different, unspecified, secret algorithm to detect squares.

Scoring

 * 1 point per line cleared
 * 1 bonus point if four lines cleared simultaneously (tetris)
 * 5 points when a 1&times;4 strip of silver square is corrupted
 * 10 points when a 1&times;4 strip of gold square is corrupted
 * no instant reward for
 * completing a 4x4 square
 * spin moves (twists)

So a tetris with all four lines of a silver square is worth 25 points (4 + 1 + 5 * 4), and a tetris with all four lines of a gold square is worth 45 points (4 + 1 + 10 * 4). The greatest possible reward for a single move is therefore 85, as in the following case:

The total of 85 is made up of:
 * 4 from the four lines cleared
 * 1 as four were cleared simultaneously
 * 10 &times; 8 = 80 as eight 1&times;4 strips of gold are cleared

Game modes
The game modes are:
 * Marathon – game continues indefinitely (or until only one player remains in multiplayer)
 * Ultra – a race to 150 lines
 * Sprint – a three minute countdown

Each mode can be single player or multiplayer. In multiplayer mode up to four players can compete, with the option of no garbage, directed garbage or hot potato garbage.

Garbage modes:
 * None – garbage is disabled
 * Directed – each player can choose the recipient of his or her garbage by using the left and right C buttons
 * Hot potato_ – one player is outlined in red and receives all garbage. When this player completes a line the hot potato moves to a random player (which could be the same one)

In single player mode a computer-controlled opponent can be activated (which also forces garbage mode on), but even on the highest skill level it is not challenging to stronger players. The CPU opponent's name is randomly selected from a set in the ROM; "Nachanca" has been seen to exploit infinity to completely prevent topping out.

Successor: "Square Tetris" mode in Tetris Worlds