You must line up 5 balls of the same color either horizontally, vertically, or
diagonally so that they will disappear, because when the board is filled with
balls the game ends.

The only balls you can move are the 3 in the upper left hand corner. In the
meantime several small fishes are floating around the board, and they can land
anywhere they please – and usually in line with 4 of the same color so you are
blocked. You can’t move any of the small fishes on the playing field, so if
you get blocked-you just have to try to move the block another way. This is
nowhere near as easy as it sound.

Renex III