Go Sudoku is simple, logical and extremely fun
Doesn't sound particularly great does it? Well it turns out that it is strangely compelling, if you like math. If you don't like to do math, and puzzles aren't your thing then ... this isn't for you. This isn't fast paced (though you are playing against a clock) but rather favours logic and certainty over wild guesses. The foundation of all of this is logic, as you play the game for a little while it you learn to look beyond what is there, to realise what are the options to fill in the remaining squares and ... well in essence your math / reasoning skills improve.
The level of math you need to work things out is minimal, in essence if you can count from 1 to 9 you're set. Ideally the remained of the requirements you'll pick up. As i said above, if you don't enjoy logical thinking the game is not going to give you much joy, but if that's something you go for, the game is a blast.
The game provides 1000 which is a fair bit, I doubt the puzzles are something most people will memorize ... but additional downloadable ones are promised to be online.
The one thing that may be a little bit of a downer is the control system, the flicking through the numbers is reasonably straight forward, but at times is a little slow. Given the limitation of the PSP the method (shoulder buttons, plus X to commit) is reasonable. Graphics is appropriate, and the music is ambient and nice.