Outside of climbable fences, your only protection from the Poison Bog is a set of wooden rafts. Try to stay high above the hazard. The Cat Power-Up is great in this level.
Stamp
It pays to stay up high. A tall wall next to a Piranha Creeper is guarded by Fire Piranha Plants. If you jump from this wall, you can reach a trapeze that takes you to the platform with the Stamp.
Green Star #1
Below the Stamp is a Clear Pipe containing the first Green Star. You’ll have to time passing through the pipe so that you don’t end up in the Poison Bog.
Green Star #2
Not far from the Checkpoint Flag is another series of fences that can be climbed. At the top is a Green Star Ring that can lead to securing the second Green Star. Snagging all of the Green Coins can be tricky, as a couple are on small moving platforms.
It helps to turn the camera enough to center yourself on a raft just before you travel down this slope to ensure that you collect all the Coins.
Green Star #3
The raft heads straight toward a Warp Box. Don’t forget to climb up the wall behind it to reach the last Green Star. You must have a Cat Power-Up in order to reach this star!