From the review:
And one of those traditions is quite how hard it can be. Success is about exploration and experimentation. The opening puzzle requires you to disguise yourself as a guard robot to gain access to the city. But first you must figure out that this is what the game wants you to do. As a long-time adventure game player itís an instinctive notion, and emulating a disguise from the surrounding objects has been the solution to dozens of gamesí puzzles over the years. But I wonder how instinctively painting a traffic cone and stealing a light bulb will come to those who didnít have such irrational logic etched into their brains as a child.
However, to ensure no one is stuck for long Machinarium offers two levels of hints. Most scenes will have a very simple clue available by clicking the bulb that appears in the top menu. A thought bubble will appear with a simple sketch indicating the key action that needs to be taken. If youíre still stuck after that, thereís a clue book that can be clicked on which will offer a detailed pictorial guide for what that location requires of you. However, to prevent lazy peeking, the book is itself a little arcade game. You must guide a key through a side scrolling hazardous route, dodging the rocks and firing at enemy spiders, until you reach a keyhole. Er, yes. Do this and the walkthrough is yours. Itís not difficult, but itís time consuming, and itís one of the best ways to put you off cheating Iíve seen. And I should add, some of the puzzles are brilliant. The butterfly wing/slide projector puzzle is a pleasure to solve, and many Ė like the popcorn/crowbar incident Ė are just so special.