Jacob N. Breetvelt

This plugin can display a sudoku puzzle diagram on your website. 
It comes with 200.000 unique puzzles in 7 different levels of difficulty. 
The number of times a puzzle is successfully solved or failed is registered. 
There is simple help and statistics available at the front-end.

WP Sudoku Plus

This plugin displays a sudoku puzzle diagram on your website that the visitor can try to solve.

HOANG WEB

A Simple Sudoku game written in PHP & javascript.
Features:
<ul>
<li>Change game size</li>
<li>you can enable to check one by one whenever you enter new item.</li>
<li>Suggest item by clicking on field you want to suggest and click on “>> Suggest me” button.</li>
</ul>
<h3>Usage</h3>
Display sudoku game on frontend we use this shortcode [hw-sudoku] to insert into post/page content or widget text.
See shortcode params in detail:
<ul>
<li>Change sudoku matrix size</li>
</ul>
[hw-sudoku size=6]
<ul>
<li>Enable check one by one sudoku item.</li>
</ul>
[hw-sudoku auto_check=1]
<ul>
<li>You can combine params like this:</li>
</ul>
[hw-sudoku size=8 auto_check=1]

Easy PHP Sudoku Game

Simple sudoku game base php and javascript

WP Sudoku Plus vs Easy PHP Sudoku Game