Here is my email to Freeseve support

I have purchased several Freeverse games over the ears and I've been
very happy so far, however I'm extremely disappointed in Sudoku for
the following reasons:

1) The game occasionally crashes on my Twin G5 Powermac - this has
not happened in the last few days.
2) Once playing in NON Windowed mode, you can no longer access the
rest of you computer until you exit the game
3) If you hit Apple/Option Esc the game force quits without the
standard confirmation question
4) If you wrongly put in a number and then remove it, you loose all
your pencil marks
5) You can't switch off the noise and music and still have the
program beep if you make a mistake by putting a number in the wrong box
6) It is impossible to disable the stupid obnoxious annoying cretin
in the bottom right hand quarter of the screen
7) There is no way to disable the obnoxious, annoying ducks and other
animation floating around the screen
8) When playing in non windowed mode, the mouse sometimes goes crazy
and the game is no longer playable with all squares highlighting
consecutively as if you were floating your mouse around the game.

Not the type of game you want on your Mac!