Every balloon collected knocks off 3 seconds. And every hit by a bird adds 3. So if you can get enough balloons and not get hit by the birds which is almost impossible - I've done it with only one hit before. This time I got to the end in 39 seconds with 2 hits (45 seconds) and got a whopping 16 balloons so my time would have been 3 seconds negative. It doesn't show negative in the counter though it just goes down to 0.0 but the trainer will let you know and give you the almighty prize.