squarehead

SquareHead is a classic turn-based puzzle game that is played on a 32x20
field. Cells of the field are painted in different colors. One player
starts on one corner of the field, another on the other. In their turn,
players "repaint" their own cell, thereby adding adjacent cells of the
same color to it. At the end, the player with the most cells wins.

The game has several levels of difficulty and minimalistic interface.