Stars

Stars are the main collectibles of Super Luigi Country that help progress to other levels. They are also a reoccurring collectible and power-up in the Super Mario series.

How to Get
Most stars in the game require you to land on them during a platform section, while some other levels require you to collect a certain amount of a specific collectable to spawn in the Star.

"Fake" Star
In Level 20, a fake Star can be found before the fire pit, getting it won't do anything. Because of this, Level 20 is the only level in the game that does not contain a Star in it.

Trivia

 * Stars are no where to be found during boss fights.