If you've played Puzzler's puzzles online via their website like myself, you'd have high expections for the DS version, but sadly I feel they have missed out on producing a product of the same quality.
What's right with it? The games themselves are fine and easily as addictive as playing online via their website. The levels are good and you can make it as challenging as you like by setting yourself a fixed time period to play for and trying to beat your previous score.
What's wrong with it? For me it was purely the graphics and a few little bugs that let this game down. As someone else has already pointed out, at times it is unresponsive to where you're clicking, so you have to tap it several times. This is particularly annoying when trying to do Wordsearches, or when trying to confirm your answer when doing Crosswords.
My main gripe however is with the Sudoku puzzles. Whoever thought grey numbers on a grey background was a good idea? If you're playing it outside in natural light it makes it very difficult to read. More annoying though is the way the pencil numbers don't align to the grid properly and overlap the edges, which means you can't easily distinguish between 6's, 8's and 9's.
Overall it's a good buy, but if you're expecting the same level of quality as you get from the puzzles on their website you'll be slightly disappointed.