The puzzles in Dr. Cat may not be unique, but the way they're presented certainly is. Dr. Cat is a therapist who briefly gives advice to other cats before you get to solve a picture puzzle related to the patient cat's problem.
The puzzles are of the picture swap-tile type, so you select one piece and then pick another to decide its destination. I think the fact that a selected piece is highlighted in green is a rather daft idea, as several of the puzzles have green scenery so it's hard to see which one you've selected.
One other gripe is that the game has no hint mode or percentage complete gauge, so when playing on hard the pieces are small enough that several can be exactly the same colour, and lack any detail to distinguish them from each other.
The visual style is relatively cartoony and amusing, but low detail, and whether you like the art style or not the puzzles will be a challenge. The puzzles are best done in the same way as a jigsaw; by completing the edges and working in from there.
There are only 12 puzzles but 3 difficulty levels, defined by the number of pieces, and the game'll keep you busy for a while if you want to get all the achievements. The price of £4.99 is about right and the puzzles are a lot of fun if done as a family or as a parent & child.
Thanks to Afilgames and PressEngine for the review code.