Good mind-exercising ap

I play this almost daily during waits at appointments, when trying to fill time, or just for fun when watching tv. Though I was hoping my skills would improve more quickly I have definitely gotten more proficient in solving these. My eyes have trouble following my small phone screen sometimes but when I use the red numbers it is easier to see.
It is somewhat a hassle to fill in the numbers when I enter my own puzzle (usually from the newspaper), but its a lot easier on my eyes to do it on phone than on paper to solve.
On occasion Ive used the cheats and it prevents frustration. Sometimes I get annoyed though when too many wrong numbers have to be removed, I wish there was a way to just erase all the incorrect ones at one time, but I have to do 3 or 4 at a time and keep going back to remember where the wrong ones were. ( remember, Im not a genius)

Joanrsm about Sudoku ~ Classic Puzzle Game, v3.36