HOLLOW

Surround empty space to clear the blocks around it. HOLLOW is a falling-block puzzle about making the gaps you would normally avoid. A sealed pocket clears the blocks touching its four sides. Bigger pockets and chain reactions score more. Your first move is guided: drop one piece, watch a pocket form, then try it yourself. Arrow keys move and rotate, Space drops, P pauses, and R restarts. On touch screens, tap the board to choose a column, then tap DROP.