Feel like this level is owed 5 stars for being one of the most difficult in the game. I was inspired to try after kjs cut it down to 263. Managed to get 269 in my first sitting, then had to come back a couple times before finally seeing the 263. Really clean solution but this is an extremely evil level.
Stuck at 527 for now but really enjoyed figuring out how to get to the exit, a lot of cool block manipulation here.
EDIT: 521! Took a break and was able to see an area to improve.