Mr Sudoku

Digital sudoku has the advantage of providing a suite of helpful features that simply can't be offered by the paper puzzles. The ability to check your work, easy keypad entry, and other tools make video game versions a delightful distraction without the worry of rubbing away with an eraser or scribbling out entries because you used a pen. Mr Sudoku squanders this heads up by failing to leverage these features in a useful way, opting instead to justify its worth by a glut of puzzles.

Two features demonstrate the point: mistake indentification and number drawing. Turning on the mistake option shades any incorrect numbers red. This would be great if the shade of red used for false entries didn't blend in so much with the yellow signifying correct numbers. Instead, the game should colour the cell red or flash the number to make the error more obvious.

When it comes to using the touchscreen to draw numbers into a puzzle, it's another case of flawed design. Mr Sudoku has trouble recognizing '8', reading it as '5'. Inputting a '4' requires drawing it in a very specific way. Writing the numeral with an open top doesn't register with the game, which could be problematic if you learnt to write that way. It's also worth noting that you can only draw numerals for use in the main cell; noting potential numbers along a cell's borders must be done using the touch keypad.

Not everything is bad news in Mr Sudoku, however. The game's best feature allows you to start and save more than one puzzle. Unlike most sudoku titles in which you're forced to to complete one puzzle before moving to the next, you can save a handful of them. Whenever you start up the game, you can select from a menu of puzzles you've saved. A handy progress bar accompanies each one, too, letting you know exactly how close you are to completion.

Expect to sink in a lot of time solving the challenging assortment of puzzles pack into Mr Sudoku. Four levels of difficult – Easy, Medium, Hard, and Very Hard – are only relative terms. They're all hard. On the easier difficulties, puzzles take more time to solve than you'd expect. At Hard and Very Hard, they become downright frustrating. Fortunately, there are hundreds of puzzles to play on each setting, so even if you spend all your time tackling Easy- and Medium-degree puzzles you'll get dozens of hours out of the game.

That's not as impressive as the 20 million grids on offer in the considerably superior Platinum Sudoku, mind, but it's still substantial value and ultimately it's what makes Mr Sudoku at all worthwhile. Its feature set is surprisingly lacking, particularly when compared to competing sudoku titles on iPhone and a poorly implemented system for drawing numbers and subdued mistake checking option essentially balance out the wealth of content here. It's competent, if unspectacular sudoku action, then.