I love Combination because it is difficult (Score 1)

I love this game because it is so difficult and does not offer any help. You get a real sense of achievement when you complete a level. Which is a really good early morning boost on the daily commute. It also really brings out my competitive side, I want to do better than my peers who also have a copy of the game. We have started emailing each other to tell which of the super hard levels we have completed. It is just like sudoku you often stare at that for 30secs not knowing what to do, but when you work it out you get a real sense of achievement.