Tetris (Sega)

Sega's 1988 Arcade version of Tetris was the version that took Japanese arcades by storm, becoming one of the most commonly known versions of the game. Due to its popularity, it became the base of rules for many other Japanese games created later on, both licensed and unlicensed. Such games include the TGM series, Tetris Plus series, Shimizu Tetris and, to less extent, DTET. It was one of the first games to instate lock delay, improving maneuverability greatly at high speeds compared to games which did not have the feature.

Gameplay specifics
Being an early game, there was only one rotation button, which rotated counterclockwise. The game also contained no wallkicks and no hard drop. However, many of the elements that exist in later games can already be seen here, such as 1G DAS movement, lock delay, ARE, and rotation/movement processed before gravity - allowing for synchro moves to be performed at 1G fall speed. One rule element not commonly seen in recent games is the existence of the field ceiling. The field height is fixed at 20 cells, and any rotation that would exceed that height would fail.

It was one of the first games to popularize the play model of playing endlessly against increasing speed for survival, as opposed to beating levels or clearing a predefined number of lines.

Details

 * Soft drop: 1G
 * Lock delay: 30 frames
 * ARE: 30 frames
 * Line clear delay: 42 frames
 * DAS: 20 frames

Current piece speed is located at C7000Ah in the RAM.
 * Speed levels, in frames per row

There are 2 ways to increase a level. The "level timer" will increase every 256 frames. If the level increases, the timer will be reset in 0. Current level timer is stored at C72336h in the RAM.
 * Level advancement requirements
 * 1) Erase 4 lines.
 * 2) Put any tetromino after the "level timer" reaches to certain value. (Level will not increase if line clear happen.)

Power-on Pattern
One characteristic of this version of Tetris was the existence of a "Power-on pattern". This referred to the game's behavior that the string of pieces it dealt in the very first game after starting up the system was always the same. This was most probably caused by the state of the randomization seed in the system. After its discovery, players began constructing gameplay plans around the power-on pattern in order to max out the score in the least lines possible. Sega's 1999 version of Tetris (Arcade, Dreamcast) pays tribute to the power-on pattern, by dealing the sequence in the final level of the single-player game.

Availability
A fairly accurate representation of the game, along with Tetris: New Century, Flash Point and Bloxeed, can be obtained in the Japanese PS2 game Sega Ages 2500 Series Vol.28 Tetris Collection.
 * Games