itch.io

Thanks, you'll have to let me know how it goes.

This issue is mentioned in Squidgemonster's video on saving a pdf. It's likely because the lines are too fine to appear when zoomed out. Try zooming in to 100% or more, they should appear. Also, when printed they should also appear, although, I've had the odd case when a grid line or two also doesn't appear in the print.