・Each stage has one or more objectives. You need to complete them within the limited number of moves/amount of time. The number of moves/amount of time will differ depending on the stage. If you complete the objectives without using up all of your moves, you will get some Canned Sardines (which is the in-game currency) as a bonus.
・You cannot go back to the stages you have already cleared (except for "Theo's Cheese Collection.")
When you complete puzzles, you will receive some Meowros, the currency used in the world of cats. The Meowros can be used to perform "tasks" (you can find your current tasks from the "Menu" button.)