You need to crack a safe with a number lock. Choose your level from 2 to 6 numbers, and work out the combination. Grey ‘O's mean right number wrong position and the green ticks mean right number, right position - somewhere in your guess.

You use the mouse or touchpad on your laptop to click. There are no keyboard controls for this game.

First choose how complex you want the number lock to be – from 2-6 digits. Then you take turns to try to guess the number. Grey 'O's mean right number, wrong position. Green ticks mean right number, right position - somewhere in your guess.

You can note number combinations here to help you. The clues you get don't tell you the order the number lock will open for, you need to work that out yourself. When you get the number right the door to the safe will open.

1) Pay attention: You need to remember what combinations of numbers you have already tried. Remember, a Grey 'O' means correct number, wrong position and try to work each number out as quickly as possible;
2) No speed limit: You can take as long as you like to complete a level.