May sound boring, but it really isn't!
If you like puzzle games, this is a must-buy. The concept is easy to understand, but the puzzles that you are required to solve vary in difficulty. In the beginning, there are puzzles which you can solve in about 30 seconds. Not too long after those puzzles though, new puzzles become available and they slowly take longer and longer to solve. This game requires a lot of thinking and logic and is very addictive.
There really isn't much else to say about this game besides that it is indeed very very fun despite what it looks like/the concept of it. Definitely one of the best puzzle games I have ever played :)