How do you free Zack on riddle transfer?

To free Zack in Riddle Transfer, you need to solve a series of puzzles that involve using items and interacting with various characters in the game. Specifically, you'll need to find the key that unlocks his cell, which is located in a different area. Once you have the key, return to Zack's location and use it to release him. Completing this task will help advance the story and allow you to continue your journey.