Marathon is a game mode where the player plays the game either until completing a fixed level, or endlessly.
Marathon in the Tetris Guideline
The Tetris Guideline defines two types of Marathon modes. Variable goal was common in the earlier years of the guideline, but since around 2010 has largely been phased out in favour of fixed goal.
- In fixed goal, each level requires 10 lines to clear. If the player starts at a later level, the number of lines required is the same as if starting at level 1.
- In variable goal, each level requires 5*L goal to clear. In games after the introduction of the current scoring system, the amount of goal given by a line clear is equal to its base score value divided by 100 and rounded down. Excess goal is not carried over between levels.
Most Guideline games have a speed curve based on the curve used in Tetris Worlds. In this speed curve, the time for a piece to move down by one row is given by the following formula:
Time = (0.8-((Level-1)*0.007))(Level-1)
Though the values produced by this formula have a huge number of decimal places, the following approximate G values retain frame-accuracy and are therefore indistinguishable from the formula.
There is no rule on how to handle the speed curve after level 19. Tetris (tetris.com) reduces the duration of lock delay between levels 20 and 30. Some variations on the speed curve have been observed; Tetris DS, for example, offsets the curve by 1 level and rounds the speed values to the nearest frame.