As @HerbieG said, there's maybe something with some of the medals not always unlocking?
When I had a high score of 99, "Maximum Speed" did not unlock, despite it had unlocked at only 81 for someone else. It unlocked for me at 105 I believe.
As for "Super Speed", at the time of HerbieG's review he was correct. That now just unlocked for me at a high score of 78 despite not unlocking at 105.
The top three medals seem to be random unlocks?
The good news is it appears someone can just keep playing the game and maybe they can get a medal that didn't randomly unlocked the last time.