The Fever gauge controls Fever Mode, a special feature that forces customers to spend much faster for a short amount of time. The stars needed to fill the gauge increase by 2 with each level and cap at level 16 (32 stars). The gauge can be filled in three ways:
- Giving a customer directions to a random structure (2 stars), which randomly happens on each floor after some time.
- Picking up one of the floating stars spawning on the screen before it reaches the top (1 star).
Once Fever Mode is triggered, the word "FEVER!" appears and the game enters fast-forward mode. Every shop or attraction on the current floor (this includes the Balloon Shop) will randomly generate their expected fees, up to a maximum of 25 Coins for each of them, even if no one is around.