Extreme Tetrom is a homage to Tetris: The Grand Master, Arika's series of Tetris games designed to become very difficult, providing new challenges to experienced players. It isn't a clone of any TGM game - it has its own difficulty curves, grading system, and surprises - but it should feel familiar to TGM players. Using a variation of Super Rotation System - the 'normal' Tetris rotation system in modern games - it should feel familiar to Tetris players who have never played a TGM game, too!
If you're used to other versions of Tetris, watch out for the special rules around 'floor kicks' (pieces getting popped up so they can rotate when they're on the ground) and lockdown. Floor kicks can't pop a piece back up into the air anymore, and the only way to reset the timeout before a piece locks down is to move it to a lower row than it's been in before - moving, rotating, or 'climbing' the piece upwards won't help. Think fast!
Think very fast indeed - once gravity is instantly spawning pieces on the floor of the well, the game still finds ways to get faster and faster, reducing the delay between piece spawns and giving you less time to maneuver on the ground.
This is Extreme Tetrom. Can you master it?
Controls
LR: Shift piece to the side
D: Soft drop
U: Hard drop
X,Z: Rotate
X+Z together: Hold piece
Modes

Marathon: A classic mode for players who want a traditional Tetris experience. How quickly can you clear 150 lines? Game speed follows a curve similar to 'standard' Tetris games.
Sprint: Marathon, but for only 40 lines.
Infinite: Played for a high score, this mode also uses a standard Tetris speed curve - although it starts doing some very TGM-like things to try to force the game to end once you've been playing for a very long time...
Grandmaster: Inspired by Arika's TGM series, this mode's speed fluctuates throughout play (until it reaches 20G, at which point it only gets harder). You'r