The difficulty level at Grubber.com.au is measured by how difficult it is to win the prize.
For example, if there is 1 prospector shown, then it is very easy to win the prize.
If the difficulty level shows 5 prospectors, then it would be very hard to win the prize.
In Sudoku it is all about being skilled and fast. You have a week to solve your sudoku, and the time starts when you click on "Play Sudoku – Hard", so it might be a good idea to be prepared when you start.
The person who correctly solves the sudoku the fastest wins a prize in the next draw.
You can play as many times as you like. The more you play, the bigger the chance of ending up with the best time and thereby winning the weekly prize.
If you do not know this classic game here is a brief summary of the rules:
Your playing board is a 9x9 grid. Some of the grid cells are already filled in and you should fill in the remaining cells with the correct numbers between 1 and 9.
The grid should be completed according to the following guidelines:
Numbers between 1-9 can appear only once in each row.
Numbers between 1-9 can appear only once in each column.
Numbers between 1-9 can appear only once in each region (3x3 fields).
If a number occurs more than once in a row, column or region the game grid is invalid.