Echoing pretty much as what's been said, images not similarly cropped and although I get the motif the spider does cause a visual disturbance when trying to find differences between the two pics. Offering a hint button once someone's score goes into the negative might be a nice touch as well.

The images aren't the same size. A big spider blocks at least one of the differences. These are fundamentally huge problems that you've managed to put into a game in which the only form of player interaction is to click on parts of a pair of images.

As for level design, in every "difference" something's simply missing from one image or the other. There's never a case of something existing in both images but just being, ya know, DIFFERENT. So all the levels feel incredibly same-y and very easy. Rather than a missing eye in a carved pumpkin, have one eye be a triangle and the other a circle. Instead of yet another missing bat, have the bat fly upside-down. Have a window change color between images instead of just not being there in one. etc

this game made find 5 mistakes its for kids first form good job

The top image is slightly cropped at the bottom. You should never do that in these types of games for obvious reasons. Also, the spider is cute but very annoyingly placed, and the game should probably have some sort of "hint" button.

Cheers,
M

ehhh