The Side A Libra Riddle requirement is as follows -
"Did not collect any small hearts in Parallel Universes".
This one is annoying, but also fair, as the level is quite short. A lot of the map/level is changing between screens and popping up hearts on other paths. So play the level enough to know where they are. Stick to the left side mainly, and when you get to the fan segments, cross sideways to the way that the hearts aren't at, so you don't collect them. The big with the ramp, and a fan at the end with only the right side open with hearts, stay on the left. A portion will open up last second, with a collectible too!