LogFAQs > #969784182

the picross S games (and the other ones on switch) have three assist options that you can turn on or off. The roulette when you start the puzzle, the hint numbers turning blue when there's one or more square that you can fill in based on the clues because they would always be filled in with any combination of filled in squares, and autocorrecting you when you try to fill in a square that shouldn't be.

If you turn them all off, you'll get a medal on your save file when you finish all the puzzles. Though, there's usually a puzzle on each page or so where you can't use any of the assist modes anyway.

There's also a menu option that lets you check all the squares to see if they're filled in properly. I never chose that so I don't know what it does or if there's any penalty attached to it.