Kirby competes against three opponents to see who can send the biggest punch. There are three parts to getting the best punch. The first part is the Power Meter. The player has to press the A button to stop the oscillating meter. The closer to the peak, the stronger the punch. The second part is the Target Rings, which are represented by two floating crosshairs. Press the button when the cross hairs exactly overlap. The third part is the Timing Pendulum. Press the button when the pendulum is exactly lined up with the green circle. If all parts are done as accurately as possible, Kirby will deliver a very strong punch (201MT.) that cracks Pop Star in half!
Mario, Luigi, Birdo, and Toad appear in the audience behind Kirby. However, they appear twice, because the audience is mirrored. This is actually the same exact audience that appears at the end of the SNES version of Spring Breeze, except Bowser is entirely out of frame and missing.
This is an unlockable sub-game in Kirby Super Star Ultra. This is one of two nostalgic sub-games, the other being Samurai Kirby. It is directly ported from the SNES version of Kirby Super Star, and thus does not see any of the enhancements featured in the DS version. The only difference is that there is no two player mode.
Due to the above, Bounder, an enemy otherwise replaced by Gip in the DS version, still makes a cameo in the audience here.