The "Alienators" have planted bombs all around the Jupiter Command Headquarters. It's up to the player to disarm them all in time!
Gameplay in Jumpman Junior is largely identical to the original Jumpman, but with 12 new levels. Once all 12 levels are completed, players continue to randomly cycle through levels until no lives remain, unlike the original game where there is a set "ending" for most of the game modes.
- Nothing to it: A basic introductory level with a single bullet.
- Fire! Fire!: Each time a bomb is collected, a fire appears in a fixed location. Fires can be jumped.
- Sreddal: Two ladders move up and down the center of the screen, and change direction whenever a bomb is touched. If a bomb is collected when the ladders are changing directions at the top or bottom of the screen the ladders can break apart into smaller segments
- Hellstones: Rather than fire from the sides of the screen, bullets fall from the top of the screen and bounce on the platforms.
- Figurit's Revenge: Each time a bomb is collected, a fixed piece of the level appears or disappears.
- Walls: Each time a bomb is collected, a colored wall begins moving from one side of the screen to the other. Another wall is added for each bomb, moving in the opposite direction of the previous wall.
- Zig Zag: Instead of firing in a straight line, bullets move in a wave pattern.
- Spellbound: Each time a bomb is collected, a letter appears in the middle of the screen. Bonus points are awarded if the player spells EPYX JUMPMAN.
- Blackout: The level is initially completely dark, and details are only revealed in a small area around the player.
- Herethereeverywhere: Whenver the player collects a bomb, they are teleported to a different location in the level.
- Hatchlings: Collecting a bomb causes an ememy bird to hatch from the last collected bomb and home in on the player.
- Hurricane: A strong wind blows from the left of the screen that the player needs to fight against to move.