What the 'Cheat' button does is, it removes all the 2s and 4s (those petty thieves!) from board. So if you feel super frustrated with a situation like "1024 | 2 | 1024" or "1024 | 4 | 1024".. no worries! Cheat is there to save the day! But mind you, you get only three Cheats per match. So be wise to cheat.