The top of the canyon offers a panoramic view of the entirety of Sand Canyon, but you must journey across the base of the canyon to reach the boss of this world. Descending from the canyon to the desert below will require some work, as the uneven terrain and treacherous enemies will do everything to slow you down. The mushrooms here have to compete for nutrients from tulips, so they will definitely appreciate anyone that can get rid of these invasive flowers.
Heart Star: The fungi's domain
The requirements to get the Heart Star appears just as the level starts. Jump over some gaps and you will see a tulip. However, unlike in previous levels, you must trample these flowers by either attacking them or walking over them. There will also be several mushrooms growing in this area, and you must avoid trampling these fungi instead of the tulips. The section itself is pretty straightforward. The main enemies are Bronto Burts and Galbos as well as Gordos, though most of the Gordos aren't right in your path, so they are not as big of a threat. The Burning ability you obtain from the Galbos can let you shoot over a mushroom or a gap, ensuring that you don't accidentally trample it or fall into a pit.
The Polof's secret stash
The section you enter will be mostly empty except for a pink puffball with rabbit ears called a Polof. This peculiar creature does nothing to harm you, and will simply hop around the screen. Eventually it will disappear into the background. While it might seem like a pointless enemy, the location the Polof disappears at is actually a hidden door leading to a secret room! You can get a ton of stars inside, as well as a nice 1-Up. Once you got everything in the secret room, continue on into the level. You will stop by at a small section to choose between Rick and Pitch.
Climbing against cannons
There are tons of Shotzos attached to various surfaces in this section. As always, they cannot be destroyed, so you must try to avoid all of their shots. There are also plenty of Oro hanging on the ceiling and the floor to further limit your movement options. After you climb to the second level with the row of three Oro, go right for a Health Drink to heal up any damage you've taken from the cannons. After that, continue ascending the level. The Burning ability will be quite handy throughout this section, as it will let you soar past any Shotzos while killing any Oro in your path.
You will encounter a new enemy here, the Gansan. These piles of rocks slowly roll toward you, and they grant you the Stone ability upon being swallowed. The Stone ability itself is quite handy in this area, since you can roll down the long slopes by turning into Stone form, crushing anything in your path. If you choose to go down the slopes normally, there are quite a few Sparkies, as well as plenty of Propellers. You also have to watch out for Babut at the end of each slope. Whether you chose to roll down the hill or simply walk down it, you will eventually reach the door at the very bottom.
This section introduces you to two more brand new enemies. The purple creatures flying in the sky are called Pterans, and they will make single attempts to home in on you before giving up and continuing on in their set path. There is also the curious cavemen called Dogan. While they are pretty harmless if you attack them directly, they can actually deflect any projectile you throw at them. This makes them simple to defeat with inhalation or an ability like Needle, but effectively makes them immune to every attack from abilities like Cutter. Run through the entire stretch of this section until you see a staircase patrolled by Dogan. Past the Dogan is the exit door.