I should have known better. The title in Amazon didn't match the title on the picture of the game, and the advert boasted an "infinite" number of puzzles (which is of course a mathematical impossibility and false advertising).
What is the main selling feature of the Nintendo DS? The touch-screen technology right?
Well some one should tell the jokers that made this game that the DS has a touch screen. The Sudoku grid stays in the top screen, and you navigate it by pressing buttons like a cheap electronic sudoku game you buy in the supermarket. And as there are no diagonal buttons, you have to go up one, left one, just to move to the next square if it is on a diagonal.
Another major flaw is that you cannot add little mini-numbers in the boxes to remind you what the number might be.
I bought this 'game' (or 'torture' as it should be called) to keep me occupied for a 9 hour flight. Now I am not even going to bother taking it with me. That is how bad it is.
If anyone still wants this, you can find my virtually untouched copy on ebay in a couple of weeks when I get back from holiday.