Your Campaign Sheet shows your current progress in the game. This allows you to reset the game to the correct state and continue to play from the point where you left off, even if someone played the game meanwhile.
The campaign is completed once you have unlocked everything. After that you can keep playing with all the unlocked elements, or reset the game to the original state.
• How many games do you need to unlock all the new game components?
• Once you have unlocked everything, how high can you push your high score?