Unlock Requirement: This level requires 80 Green Stars to unlock. To collect the Stamp in this level requires you to use Toad.
The level has Multi-Vators to get you around but a Cat Suit will do the trick in some situations all the same. You have 100 seconds so get moving!
Turn left and look for the broken floor tiles, ground pound here to reveal Green Star #1 . At the water hit the ? Block for a Double Cherry then ride the Multi-Vator across. Turn right grab another Double Cherry while avoiding the enemies then snag the Stamp by hitting the Toad Character Switch if you are playing as Toad.
Head back left past the Fire Piranha Plant to the #4 Multi-Vator. Atop this platform is Green Star #2 then you can jump over the ledge to Green Star #3 and run up the steps to cap the Goal Pole.