This game needs more testing, unfortunately, because it would appear that a couple of bugs got through.
Not only are the removed digits not being replenished quickly enough (which can waste valuable time) but there has been a few cases where the combination needed for the target number was unavailable. (This often occurs when the target is a double digit number)
Please recheck your scripting, Amidos, because, although your overall design is clever and original, the requirements for obtaining that third medal are proving frustrating to obtain.