If you are doing this for the badge and want to get done quickly, then just keep clicking. Click everywhere as fast as possible. I finished the game getting a "time bonus" on almost every level. If after clicking the whole screen you missed 1 or 2 do NOT try the whole screen again, just use the shake/reveal button to find what you missed.
 "Museum of Thieves"){kind=icon}
 "Take Something Literally"){kind=icon}
 "Castlewars"){kind=icon}