Tips from the dev, and a few level tweaks

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