Tetris The Grand Master

Tetris: The Grand Master is the first arcade game in Arika's TGM series.

Gameplay
TODO: Make sense of TGM for noobs. I mean seriously, there's score, grade, time, and a non-standard level. It's not even obvious that the whole point is a time attack.

Speed
ARE is fixed at 30 frames.

DAS is fixed at 15 frames.

Lock time is fixed at (somebody look this up).

Line Clear time is fixed at (somebody look this up).

Gravity is dependent on the level, and it ranges as follows:

The player can force constant 20G, by pressing ↓↓↓↓ ↓↓↓↓ C B A before starting the game, though this will exclude their play from the highscore list. Unlike TGM2, the lockdown time, line clear time, ARE and DAS time do not change throughout the game.

Scoring
TGM shares the same scoring gimmicks of many other Tetris games, though they are not quite implemented the same way:
 * You receive more points for clearing more lines at once.
 * Lines are worth more with each passing level. (The nature of "level" in TGM, however, means the amount of points a line is worth is constantly changing.)
 * You receive points for forcing a piece down. (Though only when this results in cleared lines!)

There are a few scoring gimmicks unique to TGM:
 * You receive a combo bonus for clearing lines with consecutive pieces.
 * You receive a bravo bonus for clearing the entire screen.

Incidentally, for all players good enough to attain the rank of S9 score becomes irrelevant and the focus changes to a time attack rather than a score attack. Nevertheless, here is a more technical description of the scoring formula:

Score = ((Level + Lines)/4 + Drop) x Lines x Combo x Bravo

Where:
 * Level is the current level you are on.
 * Lines is the number of lines you just cleared.
 * (Level + Lines)/4 is rounded up.
 * Drop is the number of spaces you manually dropped the piece. The last space your piece falls does not contribute to this, however locking the piece once it has landed will add 1 to the Drop.
 * Combo returns to 1 by default every time a piece does not clear lines. Otherwise, it is :
 * Combo = Combo - 1 + (2 x Lines - 1)
 * Bravo is equal to 4 if this piece has cleared the screen, and otherwise is 1.

Grades
In TGM1 grade is entirely determined by score. As you pass certain milestones, TGM will assign you the next grade:


 * In addition to this, to achieve Grand Master rank the player must reach grade 1 before level 300, grade S4 before level 500, grade S9 before level 999, and level 999 at or before 13:30:00.