FillBlankGrid is a precision grid-filling challenge. A regular grid appears with some cells already colored and others left blank. Tap only the blank cells to fill them and score. Tapping an already filled cell counts as a mistake, and three mistakes end the game. Early grids are small with many blanks and long timers, but higher scores enlarge the grid, reduce blank ratio, and shorten the fill window. Scan for empty slots carefully, avoid near-miss taps on colored cells, and clear every blank before time expires. Accuracy under denser grids is the path to longer runs.