Rotate and stack the falling pieces. Fill a full row to clear it before the well fills up.
A piece made of four connected blocks falls from the top of the well. Move it left or right, rotate it, and either let it fall naturally or drop it faster. When an entire horizontal row is completely filled with blocks, that row clears and everything above shifts down.
Clearing multiple rows with a single piece scores far more than clearing them one at a time — a four-line clear is worth the most. Every ten lines you clear, the level goes up and pieces fall faster. The round ends when a new piece has nowhere to appear at the top of the well.