This one stumped me at first. But only because the way that the coin needs to be collected. You have to move a block on top of it, and then update the game with the block to collect the coin. My first go at it, I honestly assumed that the game just didn't work until I messed around a second time and heard the little collect noise.
As much as I love the little square ninja turtle, I couldn't help but using the word "attached" when talking about moving 2 blocks. I wonder if changing the theme to reflect that might help with understanding of the first couple levels and might just tie everything together a bit. I personally thought about magnetic fields or electric currents binding the blocks together.
That last level was a doozy for me though. I originally thought that this concept was lacking in complexity and was just too simple to make a good game out of, but if you can continue to churn out levels that are on the same level as that last one, then I will have to stand corrected.