The trick to this level is lighting all of the unlit torches in the areas you move through, as that’s how the Green Stars appear. With that knowledge, you will need the Fire Flowers you get in the level throughout the whole thing. Also, as the name of the level suggests, you will be dealing with a lot of Piranha Creepers and you should get rid of them as you go along, as they will get in the way quite often. This is especially true if you’re going after one of the unlit torches, since it might take you a couple of tries to get a good shot off on them.
At the beginning of the stage, run past the first Creepers and hit the ?-Block for a Fire Flower, which will be needed for the Green Stars in this level. Light the braziers in the immediate area, then continue past more Creepers while doing the same thing. Once you make it to the end of the first area and light all of the braziers, you will receive Green Star #1. Defeat the Piranha Creeper blocking the pipe, then go through it to arrive in the next area. There will be another ?-Block with a Fire Flower nearby here, as well as some cloud platforms that bring you to the upper portion.
There’s nothing really up here, though, other than coins, some POW Blocks and a pipe that takes you back to where you got the Fire Flower. The lower section is where you need to go, which is much more challenging when compared to the first. The reasons for this is that the platforms are spinning, plus you have to contend with Fire Bars, Fire Piranha Plants and more Piranha Creepers. None of the braziers are hidden, so there’s nothing really to note there. Light all of them in the second area to get Green Star #2, then go through the pipe at the end. There will be three more braziers in this final area, netting you Green Star #3, then it’s a simply jump off of the Creeper to the Goal Pole.