An interesting game mechanic, and quite fun! - I thought I was running out of moves, when I kept failing - I can see now that is it a timer-based deadline...
I personally think that for such a sedate, relaxing game, it might be better to remove the timer in at least one (zen or relaxed?) mode, and perhaps reward score (ie. classic 1,2,3 stars etc) based on how many moves it took versus your set 'par', but obviously just a suggestion!
Nice idea though, and can definitely be expanded upon!