Q. How do you set a checkpoint?
A. To replay a level, a token must be used to unlock a checkpoint.

Q. How do I get more tokens?
A. Tokens can be found on the secret levels or purchased from the main menu.

Q. Secret levels?
A. Collect all pieces of the map on an island, to unlock the seventh secret level.

Q. Can I unlock all checkpoints?
A. Start every level in the entire game without a token by purchasing "Unlock all checkpoints".