Nintendo published the first official version of Tetris for Nintendo Entertainment System. Unlike Tetяis, this game has no 2-player mode.

Details

The Nintendo Entertainment System is specified to run at 60.0988 frames per second. It was first published in North America in 1985 by Nintendo Entertainment.

Rotation system is a right-handed Nintendo Rotation System. Lock delay, wall kick and hard drops were not implemented. Softdrops were allowed, and the players were rewarded 1 point per cell (Max of 20). DAS initial delay is 16 frames, and then every 6 frames. Soft drop speed is 1/2G. ARE is 10~18 frames depending on the height at which the piece locked; pieces that lock in the bottom two rows are followed by 10 frames of entry delay, and each group of 4 rows above that has an entry delay 2 frames longer than the last; line clear delay is an additional 17~20 frames depending on the frame that the piece locks; the animation has 5 steps that advance when the global frame counter modulo 4 equals 0. As a consequence, the first step of the line clear animation is not always a set number of frames.

The following table of gravity speeds was observed and later found to be stored at $898E (offset $099E in the iNES format ROM):

Level Frames per Gridcell 00 48 01 43 02 38 03 33 04 28 05 23 06 18 07 13 08 8 09 6 10–12 5 13–15 4 16–18 3 19–28 2 29+ 1





In Marathon (called A-TYPE), when the player line clear (startLevel * 10 + 10) or max(100,startLevel*10-50) lines, whatever comes first, the level advances by 1. After this, the level advances by 1 for every 10 lines.

Start at level 5, advance to level 6 at 60 lines, advance to level 7 at 70 lines.

Start at level 12, advance to level 13 at 100 lines, advance to level 14 at 110 lines.

Due to the way that line clear math works (shifting a decimal number, then forgetting to convert from hexadecimal to decimal), lines after level 20 also behave oddly.