Tetris The Grand Master 3 Terror-Instinct

Tetris The Grand Master 3 Terror-Instinct, abbreviated TGM3 or Ti, is a Tetris game from Arika, part of the TGM series.

Difference from past games in the series
The grading system has undergone significant changes from previous games. The most notable change is the removal of an in-game score and grade display; they are only displayed after the end of the game, much like the secret grade in previous games. It is thought that the grading system rewards clean stacking and efficient recovery as opposed to raw speed or tetrises.

Level Bonuses
Unlike in TGM, TGM2, and TAP, TGM3 advances the level further for a 3 or 4 line clear:

Easy
Easy mode has many similarities with Normal mode in TGM2. It is designed to bring less experienced players into the game who may be intimidated by the high speeds and steep learning curve of Master mode and Shirase mode. During play, the game displays a guide, depicted by a hollow frame, designed to give players suggestions on where to place the active tetromino.

The game also shows animations of fireworks every time a line is cleared. The total number of firework shots ("Hanabi") during play is given at the end of the game, creating a "game within a game," where the objective is to attain the highest number of fireworks possible. The number of fireworks can increase with higher line clears, combos (multiple consecutive line clears), and T-Spin line clears.

Easy mode is cleared by simply reaching level 200. Play continues during the credit roll in 20G, with a boost in the number of fireworks shown.

Sakura
Sakura mode replicates the gameplay of Tetris with Cardcaptor Sakura Eternal Heart. The mode's objective is not to clear lines but to clear every jeweled block in each stage as quickly as possible, similar to Flash Point. There are 20 stages, and 7 EX stages, each progressively more difficult to clear efficiently. Some stages feature handicaps such as the regular flipping of the playing field from left to right or the periodic invisibility of non-jewel blocks. The hold box is cleared between stages, therefore; it is not possible to hold a desired tetromino for the following stage.

Score is not recorded as the mode is purely a time attack exercise. The player has a time limit in which to complete the whole mode. Beginning at 3 minutes, a time bonus is given for quickly clearing a stage.

Master
Master in TGM3 behaves very much like its predecessor in TGM2. Notable differences include the addition of a hold piece, a 3 piece preview, and new wallkicks for T and I tetrominos. At first, these additions may make TGM3's Master mode appear easier than in TGM2. This illusion, however, is soon dispelled by a huge increase in speed, which will cause all but the most experienced of players to struggle at later levels. Unlike previous games, the rate at which the speed increases is variable, and changes according to how well the player is doing. For instance, depending on the player, the game may enter 20G as early as level 300 or as late as level 500. Master mode will stop at level 500 with no credit roll if the timer has exceeded 7 minutes (except during qualification exams where it will continue to 999 as normal).

As mentioned earlier, the player's grade is not displayed during the game but after the game has ended. The invisible challenge during the credit roll is back in TGM3, but unlike TGM2, surviving it does not necessarily lead to a GM (Grand Master) grade. The GM grade has only recently been attained by the Japanese player 'jin8' on July 28, 2007. He is currently the only player in the world to have achieved GM. Many players had previously believed that the GM grade could not be obtained through standard play.

The Secret Grade GM is awarded for the secret ">" stacking challenge in the same fashion as previous games in the series.

Shirase
Shirase follows in the footsteps of TA Death in TGM2. However, the immense speed difference is immediately apparent, and continues to increase throughout. Shirase mode does not stop at level 999 like in TA Death and Master mode, but continues to level 1300. Shirase also has other key features:

If you reach 500 with a time greater than 2:28:00 (Classic) or 3:03:00 (World) the game will stop, and you are awarded the grade S5 (assuming no REGRET! deductions).

From level 500 to 1000, a line of garbage identical to the bottom row will spawn at regular intervals.

If you reach 1000 with a time greater than 4:56:00(Classic) or 6:06:00 (World) the game will stop, and you are awarded the grade S10 (assuming no REGRET! deductions).

From level 1000 to 1300, every tetromino that spawns is made of monochrome [ ] blocks.

Ichiro Mihara, creator of the series, has stated in his blog that levels beyond 1300 exist. Methods to reach such levels are yet unknown because the 1300 barrier has not yet been broken, even at the current record clear time of 4 minutes and 23 seconds.

Grading is handled differently in Shirase mode. The game will award an S grade equivalent to the number of sections cleared; the highest grade being S13 for clearing level 1300. If the performance earns one or more "section time" REGRET! during play, the game will award an S grade lower than the number of sections cleared. REGRET! is announced if a section time exceeds 1 minute. Although there are other types of REGRET! confirmed, only the section time REGRET! appears to subtract from the player's grade.

The secret ">" stacking challenge applies to Shirase mode also, despite a significant increase in difficulty due to its speed. Secret grades awarded in Shirase mode start at m grades instead of the usual S grades.

The Shirase credit roll is a 20G, big tetromino challenge (all tetromino are twice their normal size).

Shirase Mode Timings
Fall speed is fixed at 20G. Note: that these values have been deduced through observation of gameplay videos and may contain inaccuracies.

Scoring
Score in this game is even less important than previous games. Your score is not shown until your game is finished, and it is apparently not used for the grading system or rankings. Nevertheless, the algorithm has changed since TAP, eliminating any effect from bravos and reducing the reward for sonic drops and speed. The equation is:

Score = ((Level + Lines)/4 + Soft + Sonic) x Lines x Combo + (Level_After_Clear)/2 + Speed

Where:
 * Level is the current level you are on.
 * Lines is the number of lines you just cleared. There is no bonus here for triples and tetrises.
 * (Level + Lines)/4 is rounded up.
 * (Level_After_Clear)/2 is rounded up. This is the only part of the equation where the level bonus for triples and tetrises makes a difference.
 * Soft is the cummulative number frames during which Down was held during the piece's active time. Note that this means manually locking pieces already on the ground will increase the Soft value by 1.
 * Sonic is the size of the single greatest sonic drop during the piece's active time. Note that this is non-cummulative.
 * If the previous piece cleared no lines, Combo is reset to 1. Otherwise and its Combo value is:
 * Combo = (previous Combo value) + (2 x Lines) - 2
 * Example: A double-triple-single combo will have combo values 3, 7, and 7 respectively.
 * Speed can be no less than 0, and otherwise equal to:
 * Speed = Lock Delay - Active Time
 * Where, Lock Delay is the number of frames of lock delay given out for that particular level, and Active Time is the number of frames the piece was active (which is a minimum of 1).