In the first part after the first yellow booster, there is a set of gears that you need to jump onto and run across. Difficulty: ⭐

On the part after the clock section, you can jump onto the side of the platform, jump onto the bridge, and go right while holding jump against the railing to land on the higher level faster. Difficulty: ⭐⭐⭐

On the part after the split, there is a section where you can jump onto a gear and jump to the next platform in between a path. You can jump over this and land on the other side and not touch the gear. Difficulty: ⭐

One the part with the loop, take the red pad and jump into the giant birdhouse straight ahead, and hit the yellow booster inside of it. Difficulty: ⭐