This is a level with history. :)
I first had an 580+ path. Today I found ''the'' cut and brought it down to 510, but cannot see, how to cut 12 more steps. Will be back!
EDIT (1 hour later): Got it to 506 - this is soooo vicious!
Enjoyed solving this one. It looks intimidating at first but you can mostly break it down into smaller sections as you solve it. There's enough interaction between the different sections to keep it interesting and there are some fun cuts along the way.
This is a really neat puzzle. Fantastic piecemeal puzzlework combined with a really interesting design and neat usage of the exterior to prevent core abuse.
I hope this 578 sticks! The 580 was really solid but there was a suspicious amount of wiggle room still in the puzzle that I was really hoping to eliminate.
Sir Qwerto pushed this a bit lower and made me fight to find 4 more. Found 6 but man are there a lot of little quirky things to check!