I've now finished it. Great game. It's one of those things where you need to put yourself into the mind of the author and the answers come more easily. I began to get more stuck at the end, and I think part of the reason is that I broke off playing it to test something else and then found it harder to get back into (I make quite rapid progress at first).
It's really inventive and those blocky graphics work very well. One of my favourite entries.