I got this Rube Goldberg-esqe game for a buck at Target last year. My 4 year old wanted to play it, and enjoyed it, but it seemed really difficult... until we realized there was a tutorial. The tutorial is EXCELLENT! It speaks to you so even kids who can't read can find out how each and every item behaves. Once you know that, the rest of the game is pure fun! The puzzles are quirky and punny and silly and most importantly - make you think! Once he stepped through all the tutorial, he moved on to the EASY puzzles. He has conquered most of those with a little help and has moved on to MEDIUM. We like to sit and play the DIFFICULT and EXPERT puzzles together. And if you want - and my son does - you can build your own.
For every puzzle, you can adjust the music (much better than most kids games), the background colors, the gravity and other stuff. It really is just a wonderful game.
My only gripes are these:
My son plays it too much! (and I would, too, if I let myself.) and...
You can't get their solution to the puzzle until you have solved it yourself. So when you are truly stumped, there is no help.
We also own "The Incredible Machine Returns: Contraptions" which, I believe, was made before this one. But they both have the same tutorial, so you don't have to have one before the other.