that you don't get another heroic dragon at lap 15. I had to put serious effort into this race to even make it to lap 15 let alone win. Every level above that is. Who even gets to lap 25?
Edit: language per forum rules and for the record many players make it to lap 25. And sorry to get to lap 15 you need nothing but time. Any laps after that require time and gems. If done right you can get to lap 25 for less than 200 gems.