This stage is Red-Hot Run (Castle-3) Complete Walkthrough. This complete walkthrough will provide you with a 100% video playthrough and a screenshot of where you can find all the green stars. We will also note a secret 1 UP.
Game Play Walkthrough Video
Green Star 1
Early on in the stage when the path splits into two. Go for the right path and head right again. Then go for the right path again to grab the first green star.
Green Star 2
After exiting the three clear pipes, trigger the green star ring and collect the green coins. You will have to be very careful about how you move within the square.
Green Star 3
After getting the stamp, go for the middle path to avoid spikes and getting the final green star. The jumps for this part can be tough. Check the video walkthrough if you need any help.
You’ll find it near the end while running on a path made of Donut Blocks. You will have to jump across the gap to get the stamp.
Other Notable Secrets
Secret Coin Box
At the beginning of the stage, move towards the bottom right to get a coin box.
Secret Life Room
At the second green star, you can fall into the center into a pipe room full of Goombas and a invincible star. Grab the invincible star and kill all the Gombas for four 1UP’s.