There are also enemies in each level that you can either avoid or defeat. The roads to these hidden chests are hidden until you come close to them, so you’d better inspect every corner of the level. In each level, you can also find a hidden treasure chest. Others will be resting on higher platforms or behind locked doors that will require you to solve some puzzles to reach. You can see the number of stars you need to collect at the upper right corner of the screen. To activate the portal, you have to collect a certain number of stars, which are scattered across the level.
Your objective is to activate the portal at the end of each level to complete the level.