To play Tally Maze, run the PLT Games program. (Under Unix, it’s called plt-games).
The object of Tally Maze is to help the blue ball reach the exit of the maze without being caught by the pumpkins.
the arrow keys move one step in each direction;
space and . let the pumpkins move without moving the blue ball;
z undoes the most recent move; and
n changes the maze.
As you can quickly discover, simply moving around in the maze is a recipe for failure. The pumpkins know the best route in the maze to reach your blue ball and they take it.
The n key, however, adjusts the maze. More precisely, it moves forward to the next maze in an enumeration of all 254,377,512,893,447,941,210,664,002,794,210,519,990,861,507,330,048 of the mazes that the game supports. Each maze is only a little bit different from the one before, so you have to plan ahead in order to understand how the current maze differs from the next one. (Use the undo key to help you plan.)
Beware, however, that planning ahead one maze is not enough; although one pumpkin just chases you in the current maze, the other pumpkin tries to track where you might go if you advance to the next maze and to wait for you there. Not all games are winnable (although I hope most are).