To unlock the Sweet Mystery Galaxy, Mario must board a Hungry Luma and feed it 1200 Star Bits.
Bulb Berry's Mysterious Glow
Jump on Yoshi right at the start and swallow the glowing pearberry to illuminate the invisible path. Follow him, touch the Checkpoint Flag and stop at the red platform with the five yellow stars. Grab the pearberry and walk back and turn to the right. Jump from cookie to cookie until you finally reach the Comet Medal. Hurry, because time is very short.
Back on the platform, grab the berry again and light the path ahead of you. Jump on the moving gifts and grab the extra life on the green platform. Take the fruit again and make the way bright. By means of the floating flowers, you get to the top of another berry that you need to progress further. Jump over the cookies and touch the checkpoint.
In the following section, use the yellow fruit to color all the bottom plates from blue to yellow, so that a Launch Star appears in the middle. Run through the Checkpoint Flag and with the pearberry quickly up the steps. At the top you will finally find the Power Star.
Bulb Berry’s Purple Coin Glow
Select this challenge when the Prankster Comet appears.
With this slightly simpler comet star, you have to collect all the Purple Coins. This time you have neither a time limit nor the Cosmic Clones follow you. So let it go slowly and get it to you bit by bit. Whenever the luminosity threatens to disappear, you turn back. After a short time you have the Power Star in your pocket.
Comet Medal
Keep Bulb Yoshi lit after the first curved platform. Reveal the invisible branch on the right and follow it to the medal before the berry effect expires.
Green Stars — unlock requirement
Collect all 120 regular stars and defeat Bowser again to unlock the Green Star hunt. Choose the corresponding Green Star mission from this galaxy’s mission screen. Follow the detours below rather than collecting the normal mission’s ending star.
Green Star 1
Use Bulb Yoshi to stand on the visible platform directly above the first green star. Wait for the Bulb Berry effect to expire. The platform disappears and drops you into the star, so stay centred while waiting.
Green Star 2
Near the Comet Medal, look to the right for the second star. Keep Yoshi and flutter from the revealed route towards it before the light effect wears off.
Check each numbered Green Star on the mission screen after collecting it. The routes finish immediately when the star is touched, including stars suspended over a gap.