HDOS contains 35 levels of mind blowing puzzles to crack. There is a HUGE prize at the end if you manage to unlock all security layers. Playing is easy. Swap two gems by clicking, or move gems to empty places. A level is complete when all gems are gone. Don’t give up!
Main play:
Left and right move an element, if the same elements from the row or column exceeds 3, then these elements will disappear. All the element in the screen disappear, then you win!