I really like the game - am playing it now, actually - but the puzzle design gets on my nerves. Apart from the occasional pixel-hunting, it sometimes wants you to do puzzles in a certain way when you clearly can do them in another. For example,
early in the game you need to pick up a traffic cone and paint it blue. Instead of just allowing you to use paint with the cone, you have to dip the paint in water, and then put the cone inside the now-blue water. It's infuriating.
There's also been a couple of times where I missed hotspots because I hovered over them with my cursor, while the robot itself was far away.
Still, I love the game and it does have a unique charm. I recommend it.