Level tweak:
One more intro board are added to level 3-1 and 4-3.
4-9 and 4-10 are swapped.
A few boards in 4-9 (previously 4-10) are reworked.
If you find drawn lines in these levels missing, don't panic.
5-1 rules reworked.
Bug Fix:
Fixed a bug that causes game crash in 1-?.
Functional:
When you enter a level, the first unsolved board will be shown, instead of last visited one.
Other:
I uploaded a (mostly) spoiler free guide.
Hope it can be helpful.
https://steamcommunity.com/sharedfiles/filedetails/?id=2273097339