I can't believe I misremember how this level works after beating it multiple times in the past. Really had to brute force this and ignore any misconceptions I had before. I wouldn't be surprised if I'm the main reason this got moved to PhD. My bad.
This is my favorite 20x20 classic level by far, for several reasons. Not only is solving the level just incredibly satisfying, but it is a coherent challenge. It is very easy to figure out what the overall goal of the level is, and all of the opportunities for optimization are placed in front of you. There aren't any sneaky tricks, the visuals are clean, and almost every pushable block has a distinct purpose in the puzzle-solving iterations. It isn't just a good puzzle, it's also just great design.
I had such a good laugh at this level... I did a first route that I believed to be correct, but landed 4 off... grmpffff... Then I repeated it to see where I could cut and I won! I could have swear I was repeating exactly the same, but obviously, no... ROFL
Insights