In Just Dance Machine, aliens need your help to refill the battery of their UFO with the use of your dancing skills. Five routines will randomly be chosen from a variety of them, such as Rock, Dubstep, Swimmer, Hip Hop, and Ballet. Content exclusive to Just Dance Unlimited is also available in the mode.
Before each game, players are shown which dance styles are unlocked. They are the dance styles that could show up when you play. During play, you play through 5 short routines back-to-back, based on 5 randomly chosen styles (which are not revealed until you play them).
The game's judgement system is replaced with a special system that is strictly "hit or miss". On a hit, you collect 'dance energy'; at the end, the energy collected is added up. After the game, you are given a visual representation of how much energy you collected; you earn new styles if you can collect enough during the game. That energy is added to the UFO's battery, and the 'experiment' is complete.
Sometimes, one of the 5 short routines has a disco ball which is 'Cosmic Round', which the words will also show too. With that, the background shows disco balls and the two aliens are there side by side with the dancer. The dance style is chosen randomly. In the 'Cosmic Round', you still dance as used to but the music and the routine may speed up or slow down. It may also double the amount of energy you get from a "hit". When the energy bar of the routine is full, its outline turns gold. The 'Cosmic Round' does not necessarily appear in every experiment.
Some of the routines in the feature recycles backgrounds and clothing from previous Just Dance games. For example, the Metal Guitar routine reuses Junto a Ti's background and its coach reuses the clothing from the coach of Am I Wrong, the Running Man routine reuses Walk This Way's background while its coach reuses the clothing of P1 and P2 of the same song, and the Tectonic routine recycles the background from Radical.