Repetive, not challenging.
At first, I have to say that I'm normally a huge fan of puzzle games, but this one is really bad. A one-level-tutorial would have been enough and although there are further objects added to the repertoire throughout the game, every level is self-explanatory.
What people expect of this game was a puzzle where one has to find a way to solve the puzzle, not just place a bomb to trigger a chain-reaction and that's it.
But, on the other side, the game contains no bugs (at least I've found none) and is well written. The artwork is clean and looks good. Also the physics are quite realistic. That means: 4/10 stars from me for a game with potential.
And whoever keeps on marking reasonable reviews on this game as useless, stop it! It doesn't make the game any better.