The puzzles themselves are not a challenge, the only thing that makes this game hard is the sheer abuse of a glitched system. Take level 18 for example, the concept is an easy one. Playing out that concept however is borderline impossible.
Note how the official guide, when followed block for block, will give you only 894 points out of the needed 1,000. There are levels why can be done it 2-3 blocks. You have to improvise and use your brain.