Controls[edit]
Unlike in 3-D WorldRunner, in which the player can slow down or speed up the character using up and down buttons on the controller's directional pad, Jack's movement in JJ is set at a constant rate. When fighting world bosses (end of stage challenges), however, the player is capable of moving Jack freely in all directions.
and 
: Except during boss fights, use left and right to direct Jack to run laterally across the world in either direction as he runs forward. During boss fights, use it to position Jack above the ground throughout the battle.
and 
: Only used during boss fights, where they are used it to change Jack's altitude during the battle.
: Press the A button to make Jack jump. The long the button is held down, the higher Jack will jump.
: Press the B button to make Jack fire a rocket. Except during boss fights, Jack can only fire lasers if he has first picked up a rocket item. During boss fights, Jack is granted the ability to fire whether he has picked up a rocket or not.
: Press the start a new game, or to pause the action mid-game.
: Used to activate or deactivate the 3D mode (red/cyan 3D glasses are required to view this mode properly).
Jack[edit]
Jack's basic actions consist of jumping and firing a gun. Jumping is essential to leap over canyons and is also useful for dodging enemies. Upon jumping, however, from lift-off till landing, Jack is completely defenseless, because he cannot fire his weapon while jumping. The distance of Jack's jump depends on how long the player holds the A button. In addition to jumping, Jack can also fire his gun to destroy enemies, provided that the player has obtained one. By the time the player reaches the boss at the end of any level, Jack is armed with a gun regardless of whether the player had picked one up earlier.
Items[edit]
- Shield boots: A pair of boots that grants the player invulnerability; Jack glows pink when shielded. Once Jack is struck, however, the shield is lost. The shield also vanishes upon reaching a boss fight, so Jack is unable to sustain any hits when fighting the boss. If secondary shield boots are collected, the player scores 500 points per pair.
- Gun: When armed with a gun, Jack can shoot fireballs. Secondary guns score 500 points per gun.
- Eye: When touched, the eye spells instant death for Jack, and is not defended against by a shield.
- Extra life: Increases the "Play" count by one.
- Invincibility: Similar to the star in Super Mario Bros., under invincibility the music shifts and Jack flashes alternating colors, and it only lasts for a short period of time. Invincibility protects Jack from the Eye, but doesn't prevent Jack from falling into canyons. When invincible, Jack can destroy enemies by running into them.
- Stopwatch: The stopwatch resets the time counter and appears in only a few of the eight worlds.
- Tanks: Tanks are small items spread throughout each world that can be collected to increase the player's score count and tank count. When collected, each tank scores the player fifty points. The number of tanks accrues between each level, but upon completion of each world the tanks are factored into the score count, divided at 200 points apiece. The tank count also resets upon death or game over.
- Jetpacks: Jetpacks are spread throughout each world, and in each world they are only located in a specific level. When Jack touches the jetpack, he is transported to a bonus level, denoted in each world as level B. Bonus levels are filled with tanks and columns with helpful items.