Digits 1.01

Digits is a simple puzzle game. The game objective is to remove all squares with numbers (1,2,3,4). The squares are removed in chains. You can group several squares in a chain by marking them one-by-one. A new square can be added to the chain only if it stands next to the previously marked square (on the right, left, top or bottom, but NOT diagonally) and if the numbers of all marked squares build up an increasing or decreasing series. The number of the last marked square should be greater or less the previous square number by one.