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 was attained by the Japanese player 'jin8' on July 28, 2007 and 'KAN' on Dec 27, 2007. They are currently the only players 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.

Grade Recognition System
9 -> 1, S1 -> S9, M, MK, MV, MO, MM, GM

There are several independent systems that work together to produce the final grade. The first system is just like TAP, with internal grade points reaching 100 to advance to the next internal grade. Just like TAP's 9 -> S9, there are 18 grades this system can produce. In fact, testing by colour_thief (on his personal Ti machine set to freeplay) has shown that it is very likely that this entire part of the system is exactly the same as TAP with one important difference: the combo multiplier table.

The grade point formula is the same as TAP: Awarded Grade Points = ceil(Basic Amount x Combo Multiplier) x Level Multiplier

The basic amount and decay rate is determined by your current grade, and it is exactly the same as TAP. For each new "TAP grade" you obtain, your grade gets a +1.

The combo multiplier is different than TAP. If you look closely, you will notice it uses all the same columns as TAP, but given to different line clears. Most likely, TAP uses the exact table below but an "off-by-one" programming error reads the values in the wrong order. This sort of error is very easy to make when accessing two-dimensional information from a one-dimensional array, as is the case with the combo table.

Finally, depending on the level, one of four level multipliers is applied to the awarded grade points. It is exactly the same as TAP.

This core grading system is supported by a new COOL/REGRET grading system. Ti will display COOL!! or REGRET! for many reasons, but only one of these reasons is important to the grading system. The type in question is "section COOL" given out, randomly, once per section anywhere from level *80 to *90, and the "section REGRET" given out when passing *99. If you get a COOL, and finish the section, then your grade gets a +1 modifier. It is important to emphasize that you must complete the section to receive it, and it is only applied to your grade at game over. Similarly, if you get a section REGRET when passing level X99 of a section, then your grade gets a -1 modifier. If you play strangely, to get COOL at X80 but REGRET passing X99, then there is no cancelling out. The REGRET overrides the COOL and you get a -1. If you get neither COOL not REGRET for a section, then there is no modifier awarded for that section. The final section 900-999 does not award a section COOL. If you die before 999, the highest modifier you can have is +9, which means a maximum possible grade of m9. Grades cannot be negative. So if you are at "TAP grade" 9, and you get a section REGRET -1 modifier, then the -1 will have no effect. There is no grade 10.

At this time, it is not known what the requirements for each section COOL are. Similarly, grades greater than M require strong performance during the credits. Presumably, there is another modifier system in place. More research needs to be done to find out the requirements for these higher grades.

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).

COOLs and REGRETs
When playing the game, certain text messages may momentarily show up below the playfield. Two of which, COOL!! and REGRET!, are known to appear when the player has fulfilled certain conditions.

COOL!!
COOL!! messages appear only in Master mode. There are currently 3 known triggers of the COOL!! message. They cannot be visually distinguished, but they each show up when different conditions are met.

Tetris COOL
A "Tetris COOL" appears when the player has made Tetrises in excess of a certain number of times. The required number is 3 times for 0-99, 6 times in 100-199, and 4 times for all subsequent sections. Tetrises that span across sections are not counted for the previous section or the new section. This means that for a Tetris to count towards a Tetris COOL, the player would need to make the move by level *93.

A Tetris COOL can be triggered twice in the 0-99 section if the player makes 6 Tetrises, double the number required to get it once. In other sections it is practically impossible to make double the number of required Tetrises.

Section COOL
A "Section COOL" appears at around, but not exactly on, level *80 when the player has been stacking consistently at a steady pace (the exact conditions are unclear). It may appear right before a piece spawn, or along with a line clear.

It is strongly suspected that the player's grade is incremented by 1 when he triggers a section COOL, and then enters the next section. The grade increment occurs not when the COOL is triggered, but upon the section change following it. As an exception, a section COOL does not appear in the 900-999 section.

Special COOL
A "Special COOL" appears approximately two seconds after when the player performs certain moves:


 * 3 Tetrises in a row, one right after the other
 * 2 T-spins in a row, one right after the other
 * a T-spin Triple

The T-spin conditions can stack up. Therefore, if the player makes a T-spin Triple immediately followed by a T-spin Single, he will get two COOLs in a row.

REGRET!
REGRET! messages appear to note a failing in the player's performance. There are 2 known kinds of REGRET! messages in the game. In addition to Master mode, REGRET!s can also show up in Shirase mode.

Hole REGRET
A "Hole REGRET" appears when the playfield is in a suboptimal state, namely with numerous holes and possibly steps in the landscape. It appears immediately after locking a piece, or clearing a line. It can happen multiple times per section.

Section Time REGRET
A Section Time REGRET appears when the player took longer than a set amount of time to get through a *00-*99 level section. Some examples are 1'30" for Master mode Lv. 0-100, and 1'00" for Shirase mode Lv. 0-100. The times are same for both Classic and World rule modes.

Effects on Grading
Section COOLs and REGRETs strongly affect the final grade. All other COOLs and REGRETs have no direct impact on the grade.