Tetris at tetris.com

Tetris @ tetris.com is an official singleplayer Tetris game with an endless Marathon mode. It replaced N-Blox at the site tetris.com/play-tetris in 2014. First version was programmed with Unity, later versions used Adobe Flash Player. First versions used double-bag randomizer (2 pieces of each kind in the first 14 pieces, also true for the following 14 pieces, and so on), current version uses bag randomizer and follows the Tetris guideline in every regard (SRS, Hold, 3 previews, move-reset lock delay).

Gameplay
The game has only one mode following the rule set of the endless Marathon known from other games. It can be played with keyboard or mouse. Keys are customizable and so are auto-repeat delay (DAS) and auto-repeat speed (ARR). The game features 3 different versions of Korobeiniki ("the Tetris theme") as music and also has a local highscore table.

The endless Marathon can be started at levels 1, 5, 10, 15, 20 and 25. Speed maxes out at level 30. The level increases every 10 cleared lines. For example, it is 140 lines to level 15 for a level 1 start, and 100 lines to level 15 for a level 5 start. Starting either on level 1 or level 5 is recommended for scoring purposes.

From level 1 to 20 gravity increases (level 20 is already 20G, that means pieces are pulled down immediately to the very bottom). Afterwards, lock delay is reduced (whereas the initial lock delay is about a half second). The game uses move-reset lock delay. That means every time a piece is moved or rotated, lock delay is reset and the piece is still active until the delay runs out (or the piece is moved or rotated 15 times before descending).

Soft drop yields 1 point for each soft-dropped row, hard drop yields 2 points for each dropped row. Much more points can be gained by clearing lines and performing T-Spins, combos and perfect clears (see the table below). The current level functions as a score multiplier except for drop points. T-spins yield the most points per cleared line, so using T-Spin techniques such as ST Stacking is recommended for scoring purposes.

The T-Spin Mini detection rule matches with that of Tetris Friends. T-Spin Mini Double is treated as a regular double line clear.

