Construct the Blueprint for the weapon to kill the monster which is chasing the girl, before it catches her. The quicker you kill the monster, the more points you score.

The pieces for the blueprint are hidden in the buildings in the maze at random, but some of the buildings contain bombs. Guide J.J. around the maze to find the pieces of the weapon, and place them on the blueprint located at the bottom of the screen.

If you find a bomb in one of the buildings, you must drop the bomb in the monster pit to detonate it safely, but take too long and it will explode while you are carrying it causing you to lose a life.

A monster leaves the monster pit from time to time and wander across the bottom of the screen. If it reaches the weapon start button, it causes the partially assembled weapon to fall apart. The monster must then be caught and returned to the monster pit.

Once all the pieces of the weapon are in place, you must press the start button. This causes the weapon to start firing and you can move it left and right to aim at the monster at the top of the screen pursuing the girl, before it catches her. Destroy it and you are awarded bonus points, and you move on to the next level.

Additional monsters drop down the screen from time to time, and these must be avoided as contact with them causes you to lose a life.

In later levels, the gates to the maze at the left and right of the screen may open, making it easier for you to enter and exit the maze or the maze layout may change and gates may be removed. Also there will be a monster constantly roaming the maze impeding your progress which must be avoided.

You have a speedup special ability, and when the speed button is pressed J.J. moves much faster. However, this ability is limited, and the remaining turbo boost is indicated by a bar located below the blueprint. This bar is increased whenever you fit a piece of the weapon to the blueprint.

Starting lives can be set to 2, 3, 4 or 5 (default is 3).

Game difficulty can be set to easy, medium, hard or hardest (default is easy).

Points required for an extra life can be set to 20,000, 30,000, 40,000 or 50,000 (default is 20,000).

The maze monster can be set to appear on the 2nd or 3rd level (default is 2nd level).

Use your speedup ability to negotiate the maze faster, but save some of your energy in case you collect a bomb. You do not have enough time to dispose of a bomb running at normal speed.

If a monster is sitting on the weapon start button, only return it to the monster pit when it is convenient to you, as the monster does no harm except drop the pieces of the weapon to the floor. Once the monster is removed the pieces are easy to replace on the blueprint.

There is never more than one piece of the blueprint in a house, so do not return if you have already collected a weapon piece. There will only be a bomb located there.

The firing pattern of the weapon is random, and only a few shots will actually reach the top of the screen. It will therefore be mainly luck when you kill the monster ;)