The game was very easy all throughout. Even getting 3 stars didn't take too long. Making it possible to beat a level and the game with the simplest solution is bad design. It encourages the cheap solution rather than creating the motivation to solve the puuzzles in more than one way.
If it was me creating this game, I'd recommend the more difficult solutions later on in the game while maintaining a steady learning curve for new players. The hardest solution will be subjective and would encourage players to look at the game in a different way and with more focus rather than just getting them to get a point any way they can.