The clicking is somewhat off. There are times when the cursor shows an arrow only on the "real" Waldo, which makes it pretty simple to figure out, and other times clicking doesn't appear to do anything at all.
Also, is there supposed to be a difference between the "real" Waldo and the "fakes". Looking at the images, there didn't seem to be anything that marks one as real and another as false, and I'm usually pretty good at spotting differences.