Shaun the Sheep follows the farm characters established in the animated series of the same name. Here, Shaun (the protagonist), seems to be your average sheep, even though he seems to be pretty good friends with the farm's dog, Bitzer, and he walks on his hind legs, of course.
The game's story follows Shaun as he tries to find all the sheep that have gotten out of the corral and hidden themselves about the farm (depicted in the map on the top screen). Shaun the Sheep's gameplay becomes pretty formulaic and repetitive really quickly, so there is a chance that the game's younger audience could lose interest early on. What it does have is quite a lot of backtracking, since you will be going between the dozen or so different areas of the map looking for the various sheep who seem to appear out of nowhere at times (if not them, then the item you will need to get the sheep who are currently hiding).
The basic pattern has a red star appearing on the map, when you go there Shaun will notice a sheep, and then think of the items the player needs to gather in order to get to the sheep. Each of these item's locations appear as a star on the map and then you go there to find the object that was either not selectable before, or simply didn't exist.
Most of the time, you will also have to take part in some sort of mini-game to get the sheep out of hiding and into the corral. These mini-games end up being a form of whack-a-mole, or wail on a guitar (actually you just flick off the broken notes, and let the good ones through). There are eight such mini-games and they are unlocked to be played outside of the normal game by coming across them in normal gameplay, or by finding a little chick and returning it to its mother.
Finding chicks also unlock images that are also picture-slide puzzles. You know, those annoying puzzles where the picture is all shuffled around and one space is left blank so you can slide the squares all over the place. I've always gotten pretty annoyed at those things.