Many things in life look very simple on the surface of it but in reality turn out to be much more difficult than you thought.
Addled provides a great example of this. On the surface, it's just a puzzle game where you need to push matching colored boxes together. In reality it's a brain-twisting nightmare that will cause you hours of torment.
The reason Addled is so difficult is that you can only drag the blocks left or right and drop them off ledges. Once they've fallen there's no way to push them back up again. What's more, there are special types of blocks such as ice or fire that make things even trickier.
If you like a good challenge then you'll enjoy Addled as there are 200 levels of brain-teasing block building to get through (just 20 in this demo version). It's not particularly impressive in terms of its graphics, but the soothing classical music that plays in the background helps to keep your stress levels down on the particularly fiendish levels.
One thing is for sure - you won't be finishing Addled in a hurry!