Not bad. If you finish the gsme at 0 seconds left you fail. Thats frustrating. When you click some tiles quickly 3 or more in a row it doesnt click all of them, forcing you go click slower, which can result it not going fast enough to finish the level, or failing because it didnt respond to all you're clicks and didnt do what you were trying to do. For a game thats timed i should have to worry about double checking all my clicks to make sure the Game isnt messing up. Makes me fail A Lot.