hmmm...
i'm not gonna say that it's bad, but i'm going to agree on what captainsmug wrote. the 3 second drum was getting pretty anoying after hearing it 10 times. and also adding more stuff doesn't make it that much harder, it even makes it easier in my opinion. what would make it easier is putting the items on another, harder to spot area, make them blend in more. having a time limit is ok, and shortening it on a higher level as well, but it's too long.
overall, still good for the younger ones.