There should be an option to check your square
There should be a warning red , highlighting a conflict. The NYTimes Version is much less frustrating for figuring out where one has gone amiss.
Great entertainment!
This is the best Suduko game I have found. I would just make one change— once I have completed a puzzle or realized I have screwed up several places, I would like to be able to clear the board and re-do it. If there’s a way to do that, I haven’t figured it out.