Fun casual game. 10-15 hours to play it thru once. A bit more if you want to achieve gold on everything.
The game has excellent balance. Getting gold on a scene is challenging enough that you'll end up having to play many of them multiple times, while others you'll get right away.
All achievements can be made by simply playing the game from end to end inclusive of the bonus challenges. One note: Make sure you click "next". If you click "back to menu" the game doesn't register what you've done in the scene as counting towards the achievements. I played the scenes a couple at a time so found myself clicking back to menu quite often and when I did that none of the achievements were popping up (became very obvious when I needed to fix 10 pipes and I did the one scene with six of them twice that it wasn't working).
For a couple of dollars, well worth it.