Andoku Sudoku for Android offers a simple way to play sudoku on your Android tablet and Android phone. The Android app assumes you already know how to play sudoku, and does not include a tutorial, gameplay tips, or any other sort of guidance to get you started.
There are several sudoku boards to choose from, including some with special rules or layouts. Once you pick a layout you like, you can also specify a difficulty level. Andoku offers five different levels, starting with Easy and going all the way up to Fiendish. On Easy, the board will have a few numbers already filled out for you, while fiendish will start you off with a blank board.
The in-game interface feels polished and well thought out: With basic controls making it easy to see what numbers you have left to fill in. The game even includes a "pencil mode", where you can note which numbers you think could possibly go in an individual square. There are two colours schemes you can choose from (a light one and a dark one), and you can change them at will from the settings menu.
People new to sudoku may be put off by Andoku's lack of tutorials, but advanced players should have plenty to keep them coming back. With its variety of boards and difficulty levels, Andoku is great for those that want a challenge. See also: Group test: what's the best mobile game?